PHYSICAL REVIEW LETTERS 123, 161801 (2019) offfiffi a Same-Sign W Boson Pair in Association Observation of Electroweak Production p with Two Jets in pp Collisions at s = 13 TeV with the ATLAS Detector M. Aaboud et al.* (ATLAS Collaboration) (Received 10 June 2019; published 15 October 2019) This Letter presents the observation and measurement of electroweak production of a same-sign W boson pair in association with two jets using 36.1 fb−1 of proton-proton collision data recorded at a center- pffiffiffi of-mass energy of s ¼ 13 TeV by the ATLAS detector at the Large Hadron Collider. The analysis is performed in the detector fiducial phase-space region, defined by the presence of two same-sign leptons, electron or muon, and at least two jets with a large invariant mass and rapidity difference. A total of 122 candidate events are observed for a background expectation of 69  7 events, corresponding to an observed signal significance of 6.5 standard deviations. The measured fiducial signal cross section is σ fid ¼ 2.89þ0.51 þ0.29 −0.48 ðstatÞ−0.28 ðsystÞ fb. DOI: 10.1103/PhysRevLett.123.161801 The scattering of two massive vector bosons (VBS), The W  W  jj final state has the largest ratio of electro- VV → VV with V ¼ W or Z, is an important process for weak to strong production cross sections compared to other studying the mechanism of electroweak symmetry breaking VBS diboson processes [3]; this is because at leading-order [1–3]. VBS processes involve quartic gauge-boson self- (LO) accuracy in perturbative quantum chromodynamics interactions, and the s- and t-channel exchanges of a gauge (QCD) quark-gluon and gluon-gluon initiated diagrams are or Higgs boson. The Higgs boson regularizes the VBS absent and contributions from quark and (anti-)quark amplitude by canceling out the divergencies arising from annihilation diagrams are suppressed. This ratio is of order longitudinally polarized vector bosons at high energy [4,5]. five in the fiducial phase-space region of this analysis. The These cancellations depend on the gauge structure of the s-channel VBS diagrams with trilinear self-interactions theory and are exact in the standard model (SM) [6,7]. The are absent in this final state. In addition, electroweak present measurement of W boson scattering thus serves as a diagrams not involving self-interactions are suppressed fundamental probe of the SM electroweak theory. [10], thus enhancing sensitivity of this final state to At the LHC, the VBS final state of two gauge bosons gauge-boson self couplings. Previously, an observation and two jets (VVjj) can be produced via two classes of of W  W  jj electroweak production was reported by the mechanisms. The first class, referred to as strong produc- CMS Collaboration [11] and evidence was reported by the tion, involves both strong and electroweak interactions at ATLAS Collaboration using a smaller dataset [12,13]. Born level, and features diagrams where the incoming This Letter presents the observation and measurement partons exchange color, as illustrated in Fig. 1(b). The of the electroweak production of W  W  jj events in which second class, referred to as electroweak production, both W bosons decay into an electron or muon and a involves only weak interactions at Born level [8] and includes VBS diagrams. Figure 1(b) shows a typical VBS diagram where the gauge bosons are radiated off the incoming quarks and then scatter via the quartic self- interaction vertex. In VBS processes, the incoming partons do not exchange color and typically produce the two jets with a large invariant mass and with large rapidity difference [9]. (a) (b) * Full author list given at the end of the article. FIG. 1. Representative diagrams for VVjj production where Published by the American Physical Society under the terms of two electroweak gauge bosons are radiated off quarks. (a) Strong the Creative Commons Attribution 4.0 International license. production diagrams involve both electroweak and strong inter- Further distribution of this work must maintain attribution to actions without gauge boson self-interactions. (b) In VBS the author(s) and the published article’s title, journal citation, diagrams, the gauge bosons can interact via gauge-boson self- and DOI. Funded by SCOAP3. interactions, e.g., a quartic W boson vertex. 0031-9007=19=123(16)=161801(21) 161801-1 © 2019 CERN, for the ATLAS Collaboration PHYSICAL REVIEW LETTERS 123, 161801 (2019) neutrino. This study uses 36.1 fb−1 of proton-proton (pp) with exactly five orders of the EW coupling, and at LO collision data collected by the ATLAS detector at QCD accuracy. The triboson production processes were pffiffiffi s ¼ 13 TeV. The ATLAS detector [14] is a multipurpose simulated with SHERPA v2.1.1 and the CT10NLO PDF set. particle detector with a forward-backward symmetric MADGRAPH5_AMC@NLO [35] with NNPDF3.0NLO cylindrical geometry and almost 4π coverage in solid angle PDF set and PYTHIA8.210 were used to simulate tt̄V [15]. The inner tracking detector (ID) covers jηj < 2.5 in processes at NLO QCD accuracy. pseudorapidity and consists of a silicon pixel detector, The W  W  jj electroweak production cross section is a silicon microstrip detector, and a transition radiation measured in a fiducial region defined at the particle level tracker. The ID is surrounded by a superconducting in MC simulation by requiring exactly two same-sign solenoid magnet and an almost hermetic calorimeter leptons with a transverse momentum, pT , greater than system, which provides three-dimensional reconstruction 27 GeV and jηj < 2.5; leptons are defined as electrons of particle showers up to jηj ¼ 4.9. The muon spectrometer and muons produced in W boson decays and that do not (MS) has three air-core toroidal magnets: a barrel toroid originate from τ decays. The lepton four-momentum and two end cap toroids. Three layers of precision tracking includes the four-momenta of photons inside a cone of stations with drift tubes and cathode strip chambers allow size ΔR ¼ 0.1 around the lepton. The two leptons must precise muon momentum measurement up to jηj ¼ 2.7. be separated by a distance of ΔRll > 0.3 and must have Resistive-plate and thin-gap chambers provide muon trig- an invariant mass, mll , greater than 20 GeV. The gering capability up to jηj ¼ 2.4. magnitude of the vector sum of the transverse momenta Monte Carlo (MC) simulation is used to generate signal of the two final-state neutrinos with highest pT must be and background predictions. The generated events are greater than 30 GeV. Jets are reconstructed using the processed through a detector simulation [16] based on anti-kt algorithm [36] with radius parameter R ¼ 0.4 and GEANT4 [17] and are reconstructed using the same algo- using all final-state particles, except for neutrinos and rithms as used for data. The simulation includes the effect charged leptons from W boson decays. Jets are required of multiple pp interactions per bunch crossing as detailed to have pT > 35 GeV and jηj < 4.5. Events with a in Ref. [18]. charged lepton that is within a cone of radius ΔRlj ¼ Processes producing four leptons were simulated 0.3 around a jet are vetoed. The fiducial region requires using the event generator SHERPA v2.2.2 [19–22] with the at least two jets, including one with pT > 65 GeV and NNPDF3.0NNLO [23] set of parton distribution functions another with pT > 35 GeV. The two highest-pT jets (PDF). Electroweak diboson production in association with must have an invariant mass mjj > 500 GeV and a two jets was simulated with diagrams including exactly six rapidity difference jΔyjj j > 2. orders of the EW coupling [24]. The simulation of the The fiducial cross section predicted by SHERPA for strong production processes includes diagrams with W W jj electroweak production is 2.01þ0.33   −0.23 fb. The exactly four electroweak (EW) vertices [25]. The sim- uncertainty includes independent variations of the renorm- ulation of both the W  W  jj electroweak signal and alization and factorization scales by factors of 0.5 and 2 W  W  jj strong background processes includes up to with the constraint 0.5 ≤ μF =μR ≤ 2 which contribute þ14% −11%; one additional parton at LO in QCD. For lllν and 4l it also includes uncertainties from the NNPDF3.0NNLO final states, matrix elements include up to one parton at ensemble, as well as differences between the CT14 [37] next-to-leading order (NLO) and three partons at LO in and MMHT2014 [38] PDF sets (þ2.5% −1.5%) [39]. Uncertainties QCD. All multileg processes were simulated combining in the parton shower, hadronization, and underlying-event the various final-state topologies with the MEPS merging modeling are evaluated by varying the MEPS matching algorithm [22,26] and matched to the SHERPA internal and resummation scales and amount to þ8% −1%. POWHEG parton shower, hadronization, and underlying-event mod- +PYTHIA8 predicts a signal fiducial cross section of eling [21,27]. The renormalization and factorization scales were set to the invariant mass of the four-lepton 3.08þ0.45 −0.46 fb, with the uncertainties derived using the system at the matrix-element level. A signal sample for same procedures as for the SHERPA prediction, except alternative theoretical predictions was simulated with for the uncertainty in the parton shower modeling, which POWHEG-BOX [28–31] and PYTHIA8.230 [32] at NLO is estimated as the difference relative to POWHEG QCD accuracy and employing the VBS approximation +HERWIG7 [40,41]. The SHERPA electroweak samples [33], the NNPDF3.0NLO PDF set, and renormalization suffer from a nonoptimal setting of the color flow, which and factorization scales set to the W boson mass. The Vγ leads to an excess of central jet emissions from the parton processes were simulated with exactly three EW vertices shower. Since up to one additional parton is included in using SHERPA v2.1.1 at NLO (up to one parton) or LO the matrix element of the W  W  jj electroweak sample, accuracy (up to three partons) using the CT10NLO PDF the effect on its differential distributions is reduced but set [34]. Electroweak Vγjj processes were simulated accompanied by a significant suppression of the predicted using SHERPA v2.2.4 with the NNPDF3.0NNLO PDF set, cross section [24]. 161801-2 PHYSICAL REVIEW LETTERS 123, 161801 (2019) Events are required to contain at least one recon- muons are required to satisfy medium identification structed proton interaction vertex. The vertex with the criteria [43], and to have pT > 27 GeV and jd0 =σ d0 j < 3. highest p2T sum of associated ID tracks is selected as the Signal electrons and muons are further required to be primary vertex. Electrons are reconstructed from energy isolated from nearby particles, with isolation criteria clusters in the electromagnetic calorimeter that are defined using calorimeter clusters and ID tracks. These matched to tracks reconstructed in the ID with the isolation criteria are optimized to have an efficiency requirement of a hit in the innermost pixel layer [42]. of at least 90% for pT > 25 GeV and at least 99% for Muon are reconstructed by combining ID and MS pT > 60 GeV [42,43]. For dielectron events, the electron information [43]. Electron and muon candidates must pseudorapidity is restricted to jηj < 1.37 and events satisfy loose identification criteria [42,43], have with jmee − 91.2 GeVj < 15 GeV are discarded. These pT > 6 GeV, and jηj < 2.47 and jηj < 2.7, respectively. criteria reduce the background from electron charge mis- The ID tracks associated to electron (muon) candidates reconstruction described later. Candidate events with are matched to the primary vertex by requiring their exactly two signal leptons are said to pass the full event transverse impact parameter significance to satisfy selection. jd0 =σ d0 j < 5ð10Þ; the longitudinal impact parameter The contributions from the WZ, Vγ, ZZ, tt̄V, and multiplied by the sine of the polar angle of the lepton triboson production are estimated using simulation. The candidates must satisfy jz0 sin θj < 0.5 mm. Electrons predicted event yields of the WZ and Vγ processes are and muons passing these selections are further referred normalized to data in dedicated control regions. The to as baseline leptons. normalization of the WZ background is determined using Jets are reconstructed from calorimeter energy clusters events with exactly three baseline leptons, two of which [44,45] using the anti-kt algorithm with radius parameter are required to pass the signal lepton selection, and that R ¼ 0.4. Jets are required to have pT > 30 GeV in the satisfy the dijet and Emiss T selection criteria. Events from forward region (2.4 < jηj < 4.5) and pT > 25 GeV in Vγ production enter the signal region when a photon is the central region (jηj < 2.4). Central jets with pT < misidentified as an electron. The modeling of this 60 GeV must be matched to the primary vertex [46]. Jets misidentification process in simulation is corrected using containing b hadrons (b jets) are identified in the range Z → μþ μ− γ events where a photon is emitted by a muon of jηj < 2.5 with an efficiency of 85% using techniques and then misidentified as an electron. These events are described in Ref. [47]. Selected electron, muon, and jet selected by requiring exactly two opposite-sign signal candidates are required to be nonoverlapping using the muons, one signal electron, Emiss T < 30 GeV and a procedures described in Ref. [18]. The missing trans- trilepton invariant mass satisfying 75 GeV < mμμe < verse momentum, Emiss T , is computed using selected 100 GeV. A normalization factor of 1.8 is derived from electrons, muons, and jets, and the track-based soft term this control region and used to correct the simulated Vγ defined in Ref. [48]. events. To account for the differences between the Zγ Events are selected online by single-electron or single- and Wγ processes, the full effect of this correction factor muon triggers [49]. Candidate events are selected by is assigned as a systematic uncertainty, corresponding to requiring exactly two same-sign baseline leptons, elec- 44% of the estimated Vγ yield. The relative contributions tron or muon, with mll > 20 GeV and by requiring from electroweak and strong production of WZ and Vγ Emiss T > 30 GeV. They are required to contain at least processes are estimated from simulation since this two jets, including one with pT > 65 GeV and analysis is not sensitive to their different admixtures. another with pT > 35 GeV. Events with at least one Theoretical uncertainties in the predictions of the ZZ, identified b jet are rejected in order to reduce back- Vγ, triboson, and tt̄V backgrounds vary from 20% to ground contributions from top-quark pair production (tt̄). 30% [25,50,51]. The two highest-pT jets are required to have mjj > Background contributions with nonprompt leptons are 200 GeV and jΔyjj j > 2. These jet selection criteria estimated by weighting data events from dedicated control were optimized to separate the W  W  jj electroweak regions by scale factors. These scale factors are measured in process from the strong production and other background dijet events containing exactly one lepton that is pT processes. balanced by a b jet. The b-jet requirement enhances After these selections, the dominant source of back- nonprompt lepton contributions and suppresses contribu- ground events is due to leptons originating from decays of tions from W=Z bosons, which are subtracted from data heavy-flavor hadrons and jets misidentified as electrons, using simulation. The scale factor is defined as the ratio of collectively referred to as nonprompt leptons. Additional the number of signal leptons to the number of leptons selection criteria are applied to reduce their contributions. passing a dedicated background selection. The background Signal electrons are required to satisfy tight identification leptons are required to pass the baseline lepton selection criteria [42], to have pT > 27 GeV, and to be outside the and fail the signal lepton selection, where background calorimeter transition region (1.37 < jηj < 1.52). Signal electrons are in addition required to satisfy medium 161801-3 PHYSICAL REVIEW LETTERS 123, 161801 (2019) identification criteria [42]. Moreover, the background The detector systematic uncertainties arising from the electron (muon) pT is required to be greater than mismodeling of the reconstructed objects are estimated 20(15) GeV. Separate scale factors are computed for muons primarily from data and their impact on the analysis is and for central and forward electrons. In order to reduce the assessed using simulated events. The dominant source is dependence on the underlying pT spectrum of b jets that the uncertainty of the jet energy scale, which amounts to produce nonprompt leptons, the scale factors are measured 2% for the signal and 10% for the WZ background. The as a function of the scalar sum of the background lepton pT uncertainty in the measurement of the integrated luminosity and the additional activity around the lepton. This activity, is 2.1% [52]. piso30 T , is quantified by the sum of the pT of ID tracks that The theory modeling uncertainties of the mjj distribu- are within a cone of size ΔR ¼ 0.3 around the lepton and tions predicted by SHERPA for W  W  jj and WZ processes originate from the primary vertex. are evaluated using the procedures described above. They Data events, that are weighted by the scale factors, are account for uncertainties in the total cross section, the taken from control regions defined using the full event acceptance of the fiducial selection, the modeling of the selection criteria except that one lepton is required to pass event selection efficiency and the shape of the mjj the background lepton selection and its pT is replaced with distribution. Only the latter two affect the measured fiducial pT þ piso30 T , with this sum required to be greater than cross section of the W  W  jj signal, since absolute 27 GeV. A statistically independent control region is normalization uncertainties cancel in this measurement. defined for each bin of the mjj distribution. The uncertainty The uncertainty in the modeling of the event selection of the estimated nonprompt background yields is approx- efficiency also accounts for extrapolations from the fiducial imately 50% in μ μ final states and varies between 40% phase space to the detector level, in particular for the η and 90% for e e and e μ final states. It includes the acceptance in dielectron events. Effects of the NLO systematic uncertainty of the scale factors and the statistical electroweak corrections [53] and of the interference uncertainty of the control regions. The former uncertainty is between electroweak and strong W  W  jj production derived from variations in the composition of the dijet [9] are assigned as an uncertainty in the mjj shape of control regions where these factors are measured, obtained the W  W  jj signal, amounting to 6% and 4%, respec- by varying the selection criteria. The entire method is tively. This approach is used because no event generator validated in regions enriched with nonprompt leptons from implemented the complete NLO calculation until recently tt̄ (W þ jet) events selected by requiring exactly two same- [54] and because the interference contribution is defined sign leptons and exactly one (zero) b jet among a total of at only at the leading order [8]. The overlap of the photon least (less than) two jets. In these regions, the number of radiation in the SHERPA parton shower model with the observed data events and the number of predicted back- NLO EW corrections is found to be negligible. ground events agree within their uncertainties. Signal events are categorized by their lepton flavor and Opposite-sign lepton pairs pass the full event charge into six mutually exclusive channels: e e , e μ , selection when an electron undergoes an interaction and μ μ , in order to exploit their different signal and with the detector material resulting in incorrect charge background compositions. The signal region is defined reconstruction. The probability of this charge misrecon- as mjj > 500 GeV and further split into four mjj bins, struction, ϵmisrec , is measured in Z → eþ e− events [42] optimized to increase the expected signal sensitivity. Events and it increases from about 0.1% in the central region to with 200 GeV < mjj < 500 GeV serve as additional con- a few percent for jηj > 2. The background contributions trol regions, dominated by contributions from nonprompt from electron charge misreconstruction are estimated leptons and WZ backgrounds. The resulting 30 bins of the from data using opposite-sign lepton pairs that satisfy mjj distributions in the signal and control regions are the full event selection criteria, except for the same- combined in a profile likelihood fit [55] to extract the sign requirement; these events are weighted by ϵmisrec fiducial cross section. and the electron energy loss due to the material The signal strength, a free parameter in the fit, multiplies interaction is corrected with η-dependent factors the expected fiducial W  W  jj electroweak production derived from simulation [42]. The overall method is cross section used to produce the signal template. The validated by comparing the number of observed same- signal template of reconstructed W  W  jj electroweak sign electron pairs having jmee − 91.2 GeVj < 15 GeV events also includes candidate events with electrons and with the predicted background yield, with the two muons produced in W decays into τ lepton. Since the numbers agreeing within the systematic uncertainty of fiducial cross section prediction does not include such 15%. This uncertainty is dominated by the statistical events, their fractional contribution predicted by the sim- uncertainty in the measurement of ϵmisrec , which is less ulation is removed from the fiducial cross section meas- than 10% for jηj > 2 and up to 20% in the central urement. Systematic uncertainties are included in the fit as region. The charge misreconstruction of muons is found nuisance parameters constrained by Gaussian functions. to be negligible. The WZ control region is also included in the fit as a single 161801-4 PHYSICAL REVIEW LETTERS 123, 161801 (2019) TABLE I. Summary of the data event yields, and the signal and background event yields in the signal region as obtained after the fit. The numbers are shown for the six individual channels and for all channels combined. The backgrounds from Vγ production and electron charge misreconstruction are combined in the e=γ conversions category. The other prompt category combines ZZ, VVV, and tt̄V background contributions. e þ eþ e− e− eþ μþ e− μ − μþ μþ μ− μ− Combined WZ 1.48  0.32 1.09  0.27 11.6  1.9 7.9  1.4 5.0  0.7 3.4  0.6 30  4 Nonprompt 2.2  1.1 1.2  0.6 5.9  2.5 4.7  1.6 0.56  0.05 0.68  0.13 15  5 e=γ conversions 1.6  0.4 1.6  0.4 6.3  1.6 4.3  1.1   13.9  2.9 Other prompt 0.16  0.04 0.14  0.04 0.90  0.20 0.63  0.14 0.39  0.09 0.22  0.05 2.4  0.5 W  W  jj strong 0.35  0.13 0.15  0.05 2.9  1.0 1.2  0.4 1.8  0.6 0.76  0.25 7.2  2.3 Expected background 5.8  1.4 4.1  1.1 28  4 18.8  2.6 7.7  0.9 5.1  0.6 69  7 W  W  jj electroweak 5.6  1.0 2.2  0.4 24  5 9.4  1.8 13.4  2.5 5.1  1.0 60  11 Data 10 4 44 28 25 11 122 bin and the normalization of the WZ background is in the WZ control region. Figure 3 shows the mll distri- included as a free parameter. The analysis choices maxi- bution in the signal region after the fit. mize the expected significance for the W  W  jj electro- A signal strength of 1.44þ0.26 þ0.28 −0.24 ðstatÞ−0.22 ðsystÞ is mea- weak signal predicted by SHERPA at 4.4σ. A significance of sured with respect to the SHERPA fiducial cross section 6.5σ is expected by the alternative signal sample simulated prediction for W  W  jj electroweak production, where the with POWHEG-BOX. systematic uncertainty also includes the absolute normali- Table I compares the numbers of data events in the signal zation uncertainty of this prediction. This corresponds to a region with the background and signal event yields after the fiducial signal cross section of fit; the signal region contains 122 data events, compared with a best-fit yield of 69  7 background events. By fitting σ fid ¼ 2.89þ0.51 þ0.24 −0.48 ðstatÞ−0.22 ðexp systÞ the data and background events in the signal and control þ0.14 regions, the background-only hypothesis is rejected with a × −0.16 ðmod systÞþ0.08 −0.06 ðlumiÞ fb; significance of 6.5σ. Figure 2 shows the control region events separated into categories and the mjj distribution in where the uncertainties correspond to the statistical, the signal region after the fit. All nuisance parameters remain experimental systematic, theory modeling systematic, within their 1 standard deviation uncertainty after the fit. The and luminosity uncertainties, respectively. The experimen- normalization of the WZ background is scaled by tal systematic uncertainty includes the detector systematic a factor of 0.86þ0.07 þ0.18 þ0.31 −0.07 ðstatÞ−0.08 ðexp systÞ−0.23 ðmod systÞ, uncertainties and the uncertainties in estimating all back- constrained mainly by the observed number of data events ground processes except for the WZ and W  W  jj strong ATLAS Data ATLAS Data W± W± jj electroweak 25 W± W± jj electroweak 250 s = 13 TeV, 36.1 fb-1 W± W± jj strong s = 13 TeV, 36.1 fb-1 W± W± jj strong Control regions Non-prompt Non-prompt e/ γ conversions e/ γ conversions 20 Events / bin Events / 100 GeV WZ Events / bin 200 WZ Other prompt Other prompt 50 Total uncertainty Total uncertainty 150 15 40 100 30 10 20 50 5 10 0 e− μ − e+ μ + μ−μ− μ+μ+ ± l± l± l e− e− e+ e+ 500 1000 1500 2000 2500 3000 WZ CR low mjj CRs mjj [GeV] FIG. 2. Event yields for data, signal, and background in the WZ and 200 < mjj < 500 GeV control regions (left) and the mjj distribution for events meeting all selection criteria for the signal region (right). Signal and background distributions are shown as predicted after the fit. The hatched band represents the statistical and systematic uncertainties of the background predictions added in quadrature. The backgrounds from Vγ production and electron charge misreconstruction are combined into the e=γ conversions category. The other prompt category combines ZZ, VVV, and tt̄V background contributions. The last bin on the right figure includes the overflow. 161801-5 PHYSICAL REVIEW LETTERS 123, 161801 (2019) 20 ATLAS Data W± W± jj electroweak production processes that are accounted for in the modeling s = 13 TeV, 36.1 fb-1 W± W± jj strong systematic uncertainty. Table II summarizes the impacts of Non-prompt e/ γ conversions different components of systematic uncertainty. 15 Events / 25 GeV WZ Other prompt The measured fiducial cross section includes contribu- Total uncertainty tions from both the W  W  jj electroweak production and its 10 interference with the W  W  jj strong production, estimated to be approximately 6% of the predicted fiducial cross 5 section for W  W  jj electroweak production. The fiducial cross section for the W  W  jj electroweak production, without the interference effect, is predicted by SHERPA 0 100 200 300 400 500 600 and POWHEG+PYTHIA8 to be 2.01þ0.33 þ0.45 −0.23 fb and 3.08−0.46 fb, mll [GeV] respectively. The impact on the measured fiducial cross section of using POWHEG+PYTHIA8 instead of SHERPA to FIG. 3. The mll distribution for events meeting all selection generate the mjj signal template was tested and found to be criteria for the signal region is shown as predicted after the fit. smaller than the 3.6% signal modeling uncertainty. The hatched band represents the statistical and systematic uncertainties of the background prediction added in quadrature. In summary, the electroweak VVjj production process The fitted signal strength and nuisance parameters have been was studied in the W  W  jj final p ffiffiffi using 36.1 fb state −1 propagated, with the exception of the uncertainties due to the of pp collision data recorded at s ¼ 13 TeV by the interference and electroweak corrections for which a flat un- ATLAS detector at the LHC. This process includes VBS certainty is assigned. The backgrounds from Vγ production and diagrams that probe the mechanism of electroweak electron charge misreconstruction are combined in the e=γ symmetry breaking. An excess of events is observed conversions category. The other prompt category combines and the background-only hypothesis is rejected with a ZZ, VVV, and tt̄V background contributions. The last bin of significance of 6.5σ. The fiducial cross section for the distribution includes the overflow. W  W  jj electroweak production is measured to be σ fid ¼ 2.89þ0.51 þ0.24 þ0.14 þ0.08 −0.48 ðstatÞ−0.22 ðexp systÞ−0.16 ðmod systÞ−0.06 ðlumiÞ fb. TABLE II. Impact of different components of systematic uncertainty on the measured fiducial cross section, without We thank CERN for the very successful operation of the taking into account correlations. The impact of one source of LHC, as well as the support staff from our institutions systematic uncertainty is computed by first performing the fit without whom ATLAS could not be operated efficiently. with the corresponding nuisance parameter fixed to 1 standard We acknowledge the support of ANPCyT, Argentina; deviation up or down from the value obtained in the nominal fit, YerPhI, Armenia; ARC, Australia; BMWFW and FWF, then these up and down variations are symmetrized. The impacts Austria; ANAS, Azerbaijan; SSTC, Belarus; CNPq and of several sources of systematic uncertainty are added in quad- FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; rature for each component. The categorization of sources of CONICYT, Chile; CAS, MOST and NSFC, China; systematic uncertainties into experimental and theory modeling COLCIENCIAS, Colombia; MSMT CR, MPO CR and correspond to those used for the measured fiducial cross section. VSC CR, Czech Republic; DNRF and DNSRC, Denmark; Source Impact [%] IN2P3-CNRS, CEA-DRF/IRFU, France; SRNSFG, Georgia; BMBF, HGF, and MPG, Germany; GSRT, Experimental Greece; RGC, Hong Kong SAR, China; ISF, I-CORE Electron energy scale and resolution, and efficiency 0.6 and Benoziyo Center, Israel; INFN, Italy; MEXT and Muon momentum scale and resolution, and efficiency 1.3 JSPS, Japan; CNRST, Morocco; NWO, Netherlands; Jet energy and Emiss T scale and resolution 3.2 RCN, Norway; MNiSW and NCN, Poland; FCT, b-tagging inefficiency 2.1 Portugal; MNE/IFA, Romania; MES of Russia and NRC Pileup modeling 1.6 KI, Russian Federation; JINR; MESTD, Serbia; MSSR, Background, statistical 3.2 Slovakia; ARRS and MIZŠ, Slovenia; DST/NRF, South Background, misid. leptons 3.3 Background, charge misrec. 0.3 Africa; MINECO, Spain; SRCSwedish researchand Background, other 1.8 Wallenberg Foundation, Sweden; SERI, SNSF and Cantons of Bern and Geneva, Switzerland; MOST, Theory modeling Taiwan; TAEK, Turkey; STFC, United Kingdom; DOE W  W  jj electroweak-strong interference 1.0 W  W  jj electroweak, EW corrections 1.4 and NSF, United States of America. In addition, individual W  W  jj electroweak, shower, scale, PDF & αs 2.8 groups and members have received support from BCKDF, W  W  jj strong 2.9 the Canada Council, CANARIE, CRC, Compute Canada, WZ 3.3 FQRNT, and the Ontario Innovation Trust, Canada; EPLANET, ERC, ERDF, FP7, Horizon 2020 and Marie Luminosity 2.4 Skłodowska-Curie Actions, European Union; 161801-6 PHYSICAL REVIEW LETTERS 123, 161801 (2019) Investissements d’Avenir Labex and Idex, ANR, Région couplings with the ATLAS detector, Phys. Rev. D 96, Auvergne and Fondation Partager le Savoir, France; DFG 012007 (2017). and AvH Foundation, Germany; Herakleitos, Thales and [14] ATLAS Collaboration, The ATLAS experiment at the Aristeia programmes co-financed by EU-ESF and the CERN large hadron collider, J. Instrum. 3, S08003 (2008). [15] ATLAS uses a right-handed coordinate system with its Greek NSRF; BSF, GIF and Minerva, Israel; BRF, origin at the nominal interaction point (IP) in the center of Norway; CERCA Programme Generalitat the detector and the z axis along the beam direction. The de Catalunya, Generalitat Valenciana, Spain; the Royal x axis points from the IP to the center of the LHC ring, and Society and Leverhulme Trust, United Kingdom. The the y axis points upward. Cylindrical coordinates ðr; ϕÞ are crucial computing support from all WLCG partners is used in the ðx; yÞ plane, ϕ being the azimuthal angle acknowledged gratefully, in particular from CERN, the around the beam direction. The rapidity is defined as ATLAS Tier-1 facilities at TRIUMF (Canada), NDGF y ¼ 12 ln ½ðE þ pz Þ=ðE − pz Þ, where E is the energy of (Denmark, Norway, Sweden), CC-IN2P3 (France), KIT/ the particle and pz is the projection of the momentum GridKA (Germany), INFN-CNAF (Italy), NL-T1 along the z axis. The pseudorapidity is defined in terms of the polar angle θ as η ¼ − ln tanðθ=2Þ. pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ffi The distance ΔR is (Netherlands), PIC (Spain), ASGC (Taiwan), RAL (UK) 2 2 and BNL (USA), the Tier-2 facilities worldwide and large defined as ΔR ¼ ðΔηÞ þ ðΔϕÞ . [16] ATLAS Collaboration, The ATLAS simulation infrastruc- non-WLCG resource providers. Major contributors of ture, Eur. Phys. J. C 70, 823 (2010). computing resources are listed in Ref. [56]. [17] S. Agostinelli et al., GEANT4—A simulation toolkit, Nucl. Instrum. Methods Phys. Res., Sect. A 506, 250 (2003). [18] ATLAS Collaboration, Measurement of the cross-section for producing a W boson pffiffiffi in association with a single top quark in pp collisions at s ¼ 13 TeV with ATLAS, J. High [1] M. S. Chanowitz and M. Golden, Like-Charged Gauge- Energy Phys. 01 (2018) 063. Boson Pairs as a Probe of Electroweak Symmetry Breaking, [19] T. Gleisberg, S. Höche, F. Krauss, M. Schönherr, S. Phys. Rev. Lett. 61, 1053 (1988); Erratum, Phys. Rev. Lett. Schumann, F. Siegert, and J. Winter, Event generation with 63, 466(E) (1989). SHERPA 1.1, J. High Energy Phys. 02 (2009) 007. [2] J. Bagger, V. Barger, K. Cheung, J. Gunion, T. Han, G. A. [20] T. Gleisberg and S. Höche, Comix, a new matrix element Ladinsky, R. Rosenfeld, and C.-P. Yuan, Strongly interact- generator, J. High Energy Phys. 12 (2008) 039. ing WW system: Gold-plated modes, Phys. Rev. D 49, 1246 [21] S. Schumann and F. Krauss, A Parton shower algorithm (1994). [3] J. Bagger, V. Barger, K. Cheung, J. Gunion, T. Han, G. A. based on Catani-Seymour dipole factorisation, J. High Ladinsky, R. Rosenfeld, and C.-P. Yuan, CERN LHC Energy Phys. 03 (2008) 038. analysis of the strongly interacting WW system: Gold- [22] S. Höche, F. Krauss, S. Schumann, and F. Siegert, QCD plated modes, Phys. Rev. D 52, 3878 (1995). matrix elements and truncated showers, J. High Energy [4] B. W. Lee, C. Quigg, and H. B. Thacker, Strength of Weak Phys. 05 (2009) 053. Interactions at Very High-Energies and the Higgs Boson [23] R. D. Ball et al., Parton distributions for the LHC Run II, Mass, Phys. Rev. Lett. 38, 883 (1977). J. High Energy Phys. 04 (2015) 040. [5] B. W. Lee, C. Quigg, and H. B. Thacker, Weak interactions [24] ATLAS Collaboration, Modelling of the vector boson at very high energies: The role of the Higgs-boson mass, scattering process pp → W  W  jj in Monte Carlo gener- Phys. Rev. D 16, 1519 (1977). ators in ATLAS, CERN Report No. ATL-PHYS-PUB-2019- [6] G. ’t Hooft and M. J. G. Veltman, Regularization and re- 004, 2019, https://cds.cern.ch/record/2655303. normalization of gauge fields, Nucl. Phys. B44, 189 (1972). [25] ATLAS Collaboration, Multi-Boson simulation for 13 TeV [7] M. Veltman, Second threshold in weak interactions, Acta ATLAS analyses, CERN Report No. ATL-PHYS-PUB- Phys. Pol. B 8, 475 (1977). 2017-005, 2017, http://cds.cern.ch/record/2261933. [8] B. Biedermann, A. Denner, and M. Pellen, Complete NLO [26] S. Höche, F. Krauss, M. Schönherr, and F. Siegert, QCD corrections to W þ Wþ scattering and its irreducible back- matrix elements þ parton showers: The NLO case, J. High ground at the LHC, J. High Energy Phys. 10 (2017) 124. Energy Phys. 04 (2013) 027. [9] A. Ballestrero et al., Precise predictions for same-sign W- [27] M. Schönherr and F. Krauss, Soft photon radiation in particle boson scattering at the LHC, Eur. Phys. J. C 78, 671 (2018). decays in SHERPA, J. High Energy Phys. 12 (2008) 018. [10] M. Szleper, The Higgs boson and the physics of WW scat- [28] B. Jäger and G. Zanderighi, NLO corrections to electroweak tering before and after Higgs discovery, arXiv:1412.8367. and QCD production of W þ W þ plus two jets in the [11] CMS Collaboration, Observation of Electroweak Produc- POWHEG BOX, J. High Energy Phys. 11 (2011) 055. tion of Same-Sign W Boson Pairs in the Two Jet and Two [29] P. Nason, A new method for combining NLO QCD with Same-Sign Lepton Final State in Proton-Proton Collisions at shower Monte Carlo algorithms, J. High Energy Phys. 11 pffiffiffi s ¼ 13 TeV, Phys. Rev. Lett. 120, 081801 (2018). (2004) 040. [12] ATLAS Collaboration, Evidence for p Electroweak Produc- [30] S. Frixione, P. Nason, and C. Oleari, Matching NLO QCD ffiffiffi tion of W  W  jj in pp Collisions at s ¼ 8 TeV with the computations with parton shower simulations: the POW- ATLAS Detector, Phys. Rev. Lett. 113, 141803 (2014). HEG method, J. High Energy Phys. 11 (2007) 070. [13] ATLAS Collaboration, Measurement of W  W  vector- [31] S. Alioli, P. Nason, C. Oleari, and E. Re, A general boson scattering and limits on anomalous quartic gauge framework for implementing NLO calculations in shower 161801-7 PHYSICAL REVIEW LETTERS 123, 161801 (2019) Monte Carlo programs: the POWHEG BOX, J. High Energy [44] ATLAS Collaboration, Topological cell clustering in the Phys. 06 (2010) 043. ATLAS calorimeters and its performance in LHC Run 1, [32] T. Sjöstrand, S. Ask, J. R. Christiansen, R. Corke, N. Desai, Eur. Phys. J. C 77, 490 (2017). P. Ilten, S. Mrenna, S. Prestel, C. O. Rasmussen, and P. Z. [45] ATLAS Collaboration, Jet energy scale measurements and Skands, An introduction to PYTHIA 8.2, Comput. Phys. their pffiffiffi systematic uncertainties in proton-proton collisions at Commun. 191, 159 (2015). s ¼ 13 TeV with the ATLAS detector, Phys. Rev. D 96, [33] B. Jäger, C. Oleari, and D. Zeppenfeld, Next-to-leading order 072002 (2017). QCD corrections to W þ W þ jj and W − W − jj production via [46] ATLAS Collaboration, Performance pofffiffiffi pile-up mitigation weak-boson fusion, Phys. Rev. D 80, 034022 (2009). techniques for jets in pp collisions at s ¼ 8 TeV using the [34] H.-L. Lai, M. Guzzi, J. Huston, Z. Li, P. M. Nadolsky, J. ATLAS detector, Eur. Phys. J. C 76, 581 (2016). Pumplin, and C.-P. Yuan, New parton distributions for [47] ATLAS Collaboration, Measurements of b-jet tagging collider physics, Phys. Rev. D 82, 074024 (2010). efficiency pffiffiffi with the ATLAS detector using tt̄ events at [35] J. Alwall, R. Frederix, S. Frixione, V. Hirschi, F. Maltoni, O. s ¼ 13 TeV, J. High Energy Phys. 08 (2018) 089. Mattelaer, H.-S. Shao, T. Stelzer, P. Torrielli, and M. Zaro, [48] ATLAS Collaboration, Performance of missing transverse The automated computation of tree-level and next-to- momentum reconstruction with pffiffiffi the ATLAS detector using leading order differential cross sections, and their matching proton-proton collisions at s ¼ 13 TeV, Eur. Phys. J. C to parton shower simulations, J. High Energy Phys. 07 78, 903 (2018). (2014) 079. [49] ATLAS Collaboration, Performance of the ATLAS trigger [36] M. Cacciari, G. P. Salam, and G. Soyez, The anti-kt jet system in 2015, Eur. Phys. J. C 77, 317 (2017). clustering algorithm, J. High Energy Phys. 04 (2008) 063. [50] ATLAS Collaboration, Multi-Boson simulation for 13 TeV [37] S. Dulat, T.-J. Hou, J. Gao, M. Guzzi, J. Huston, P. ATLAS analyses, CERN Report No. ATL-PHYS-PUB- Nadolsky, J. Pumplin, C. Schmidt, D. Stump, and C.-P. 2016-002, 2016, https://cds.cern.ch/record/2119986. Yuan, New parton distribution functions from a global [51] LHC Higgs Cross SectionWorking Group, Handbook of analysis of quantum chromodynamics, Phys. Rev. D 93, LHC Higgs cross sections: 4. Deciphering the Nature of the 033006 (2016). Higgs sector, arXiv:1610.07922. [38] L. A. Harland-Lang, A. D. Martin, P. Motylinski, and R. S. [52] ATLAS Collaboration, pffiffiffi Luminosity determination in pp Thorne, Parton distributions in the LHC era: MMHT 2014 collisions at s ¼ 13 TeV using the ATLAS detector at PDFs, Eur. Phys. J. C 75, 204 (2015). the LHC, CERN Report No. ATLAS-CONF-2019-021, [39] J. Butterworth et al., PDF4LHC recommendations for LHC 2019, http://cds.cern.ch/record/2677054. Run II, J. Phys. G 43, 023001 (2016). [53] B. Biedermann, A. Denner, and M. Pellen, Large Electroweak [40] M. Bahr et al., Herwig++ physics and manual, Eur. Phys. Corrections to Vector-Boson Scattering at the Large Hadron J. C 58, 639 (2008). Collider, Phys. Rev. Lett. 118, 261801 (2017). [41] J. Bellm et al., Herwig 7.0/Herwig++ 3.0 release note, Eur. [54] M. Chiesa, A. Denner, J.-N. Lang, and M. Pellen, An event Phys. J. C 76, 196 (2016). generator for same-sign W-boson scattering at the LHC including [42] ATLAS Collaboration, Electron reconstruction and identi- electroweak corrections, Eur. Phys. J. C 79, 788 (2019). fication in the ATLAS experiment usingpthe [55] K. Cranmer, G. Lewis, L. Moneta, A. Shibata, and W. ffiffiffi 2015 and 2016 Verkerke, HistFactory: A tool for creating statistical models LHC proton-proton collision data at s ¼ 13 TeV, Eur. for use with RooFit and RooStats, 2012, http://cds.cern.ch/ Phys. J. C 79, 639 (2019). record/1456844/. [43] ATLAS Collaboration, Muon reconstruction performance of [56] ATLAS Collaboration, ATLAS computing acknowledge- the ATLAS detector in proton-proton collision data at pffiffiffi ments, CERN Report No. ATL-GEN-PUB-2016-002, s ¼ 13 TeV, Eur. Phys. J. C 76, 292 (2016). https://cds.cern.ch/record/2202407. M. Aaboud,35d G. Aad,100 B. Abbott,127 O. Abdinov,13,a B. Abeloos,131 D. K. Abhayasinghe,92 S. H. Abidi,166 O. S. AbouZeid,40 N. L. Abraham,155 H. Abramowicz,160 H. Abreu,159 Y. Abulaiti,6 B. S. Acharya,65a,65b,b S. Adachi,162 L. Adam,98 C. Adam Bourdarios,131 L. Adamczyk,82a J. Adelman,120 M. Adersberger,113 A. Adiguzel,12c T. Adye,143 A. A. Affolder,145 Y. Afik,159 C. Agheorghiesei,27c J. A. Aguilar-Saavedra,139f,139a F. Ahmadov,78,c G. Aielli,72a,72b S. Akatsuka,84 T. P. A. Åkesson,95 E. Akilli,53 A. V. Akimov,109 G. L. Alberghi,23b,23a J. Albert,175 P. Albicocco,50 M. J. Alconada Verzini,87 S. Alderweireldt,118 M. Aleksa,36 I. N. Aleksandrov,78 C. Alexa,27b T. Alexopoulos,10 M. Alhroob,127 B. Ali,141 G. Alimonti,67a J. Alison,37 S. P. Alkire,147 C. Allaire,131 B. M. M. Allbrooke,155 B. W. Allen,130 P. P. Allport,21 A. Aloisio,68a,68b A. Alonso,40 F. Alonso,87 C. Alpigiani,147 A. A. Alshehri,56 M. I. Alstaty,100 B. Alvarez Gonzalez,36 D. Álvarez Piqueras,173 M. G. Alviggi,68a,68b B. T. Amadio,18 Y. Amaral Coutinho,79b A. Ambler,102 L. Ambroz,134 C. Amelung,26 D. Amidei,104 S. P. Amor Dos Santos,139a,139c S. Amoroso,45 C. S. Amrouche,53 C. Anastopoulos,148 L. S. Ancu,53 N. Andari,144 T. Andeen,11 C. F. Anders,60b J. K. Anders,20 K. J. Anderson,37 161801-8 PHYSICAL REVIEW LETTERS 123, 161801 (2019) A. Andreazza,67a,67b V. Andrei,60a C. R. Anelli,175 S. Angelidakis,38 I. Angelozzi,119 A. Angerami,39 A. V. Anisenkov,121b,121a A. Annovi,70a C. Antel,60a M. T. Anthony,148 M. Antonelli,50 D. J. A. Antrim,170 F. Anulli,71a M. Aoki,80 J. A. Aparisi Pozo,173 L. Aperio Bella,36 G. Arabidze,105 J. P. Araque,139a V. Araujo Ferraz,79b R. Araujo Pereira,79b A. T. H. Arce,48 R. E. Ardell,92 F. A. Arduh,87 J-F. Arguin,108 S. Argyropoulos,76 A. J. Armbruster,36 L. J. Armitage,91 A. Armstrong,170 O. Arnaez,166 H. Arnold,119 M. Arratia,32 O. Arslan,24 A. Artamonov,110,a G. Artoni,134 S. Artz,98 S. Asai,162 N. Asbah,58 E. M. Asimakopoulou,171 L. Asquith,155 K. Assamagan,29 R. Astalos,28a R. J. Atkin,33a M. Atkinson,172 N. B. Atlay,150 K. Augsten,141 G. Avolio,36 R. Avramidou,59a M. K. Ayoub,15a A. M. Azoulay,167b G. Azuelos,108,d A. E. Baas,60a M. J. Baca,21 H. Bachacou,144 K. Bachas,66a,66b M. Backes,134 P. Bagnaia,71a,71b M. Bahmani,83 H. Bahrasemani,151 A. J. Bailey,173 J. T. Baines,143 M. Bajic,40 C. Bakalis,10 O. K. Baker,182 P. J. Bakker,119 D. Bakshi Gupta,8 S. Balaji,156 E. M. Baldin,121b,121a P. Balek,179 F. Balli,144 W. K. Balunas,136 J. Balz,98 E. Banas,83 A. Bandyopadhyay,24 Sw. Banerjee,180,e A. A. E. Bannoura,181 L. Barak,160 W. M. Barbe,38 E. L. Barberio,103 D. Barberis,54b,54a M. Barbero,100 T. Barillari,114 M-S. Barisits,36 J. Barkeloo,130 T. Barklow,152 R. Barnea,159 S. L. Barnes,59c B. M. Barnett,143 R. M. Barnett,18 Z. Barnovska-Blenessy,59a A. Baroncelli,73a G. Barone,29 A. J. Barr,134 L. Barranco Navarro,173 F. Barreiro,97 J. Barreiro Guimarães da Costa,15a R. Bartoldus,152 A. E. Barton,88 P. Bartos,28a A. Basalaev,137 A. Bassalat,131,f R. L. Bates,56 S. J. Batista,166 S. Batlamous,35e J. R. Batley,32 M. Battaglia,145 M. Bauce,71a,71b F. Bauer,144 K. T. Bauer,170 H. S. Bawa,31,g J. B. Beacham,125 T. Beau,135 P. H. Beauchemin,169 P. Bechtle,24 H. C. Beck,52 H. P. Beck,20,h K. Becker,51 M. Becker,98 C. Becot,45 A. Beddall,12d A. J. Beddall,12a V. A. Bednyakov,78 M. Bedognetti,119 C. P. Bee,154 T. A. Beermann,75 M. Begalli,79b M. Begel,29 A. Behera,154 J. K. Behr,45 A. S. Bell,93 G. Bella,160 L. Bellagamba,23b A. Bellerive,34 M. Bellomo,159 P. Bellos,9 K. Belotskiy,111 N. L. Belyaev,111 O. Benary,160,a D. Benchekroun,35a M. Bender,113 N. Benekos,10 Y. Benhammou,160 E. Benhar Noccioli,182 J. Benitez,76 D. P. Benjamin,48 M. Benoit,53 J. R. Bensinger,26 S. Bentvelsen,119 L. Beresford,134 M. Beretta,50 D. Berge,45 E. Bergeaas Kuutmann,171 N. Berger,5 B. Bergmann,141 L. J. Bergsten,26 J. Beringer,18 S. Berlendis,7 N. R. Bernard,101 G. Bernardi,135 C. Bernius,152 F. U. Bernlochner,24 T. Berry,92 P. Berta,98 C. Bertella,15a G. Bertoli,44a,44b I. A. Bertram,88 G. J. Besjes,40 O. Bessidskaia Bylund,181 M. Bessner,45 N. Besson,144 A. Bethani,99 S. Bethke,114 A. Betti,24 A. J. Bevan,91 J. Beyer,114 R. Bi,138 R. M. Bianchi,138 O. Biebel,113 D. Biedermann,19 R. Bielski,36 K. Bierwagen,98 N. V. Biesuz,70a,70b M. Biglietti,73a T. R. V. Billoud,108 M. Bindi,52 A. Bingul,12d C. Bini,71a,71b S. Biondi,23b,23a M. Birman,179 T. Bisanz,52 J. P. Biswal,160 C. Bittrich,47 D. M. Bjergaard,48 J. E. Black,152 K. M. Black,25 T. Blazek,28a I. Bloch,45 C. Blocker,26 A. Blue,56 U. Blumenschein,91 S. Blunier,146a G. J. Bobbink,119 V. S. Bobrovnikov,121b,121a S. S. Bocchetta,95 A. Bocci,48 D. Boerner,181 D. Bogavac,113 A. G. Bogdanchikov,121b,121a C. Bohm,44a V. Boisvert,92 P. Bokan,171,52 T. Bold,82a A. S. Boldyrev,112 A. E. Bolz,60b M. Bomben,135 M. Bona,91 J. S. Bonilla,130 M. Boonekamp,144 A. Borisov,122 G. Borissov,88 J. Bortfeldt,36 D. Bortoletto,134 V. Bortolotto,72a,72b D. Boscherini,23b M. Bosman,14 J. D. Bossio Sola,30 K. Bouaouda,35a J. Boudreau,138 E. V. Bouhova-Thacker,88 D. Boumediene,38 S. K. Boutle,56 A. Boveia,125 J. Boyd,36 D. Boye,33b I. R. Boyko,78 A. J. Bozson,92 J. Bracinik,21 N. Brahimi,100 A. Brandt,8 G. Brandt,181 O. Brandt,60a F. Braren,45 U. Bratzler,163 B. Brau,101 J. E. Brau,130 W. D. Breaden Madden,56 K. Brendlinger,45 L. Brenner,45 R. Brenner,171 S. Bressler,179 B. Brickwedde,98 D. L. Briglin,21 D. Britton,56 D. Britzger,114 I. Brock,24 R. Brock,105 G. Brooijmans,39 T. Brooks,92 W. K. Brooks,146b E. Brost,120 J. H Broughton,21 P. A. Bruckman de Renstrom,83 D. Bruncko,28b A. Bruni,23b G. Bruni,23b L. S. Bruni,119 S. Bruno,72a,72b B. H. Brunt,32 M. Bruschi,23b N. Bruscino,138 P. Bryant,37 L. Bryngemark,45 T. Buanes,17 Q. Buat,36 P. Buchholz,150 A. G. Buckley,56 I. A. Budagov,78 M. K. Bugge,133 F. Bührer,51 O. Bulekov,111 D. Bullock,8 T. J. Burch,120 S. Burdin,89 C. D. Burgard,119 A. M. Burger,5 B. Burghgrave,120 K. Burka,83 S. Burke,143 I. Burmeister,46 J. T. P. Burr,134 V. Büscher,98 E. Buschmann,52 P. J. Bussey,56 J. M. Butler,25 C. M. Buttar,56 J. M. Butterworth,93 P. Butti,36 W. Buttinger,36 A. Buzatu,157 A. R. Buzykaev,121b,121a G. Cabras,23b,23a S. Cabrera Urbán,173 D. Caforio,141 H. Cai,172 V. M. M. Cairo,2 O. Cakir,4a N. Calace,53 P. Calafiura,18 A. Calandri,100 G. Calderini,135 P. Calfayan,64 G. Callea,41b,41a L. P. Caloba,79b S. Calvente Lopez,97 D. Calvet,38 S. Calvet,38 T. P. Calvet,154 M. Calvetti,70a,70b R. Camacho Toro,135 S. Camarda,36 D. Camarero Munoz,97 P. Camarri,72a,72b D. Cameron,133 R. Caminal Armadans,101 C. Camincher,36 S. Campana,36 M. Campanelli,93 A. Camplani,40 A. Campoverde,150 V. Canale,68a,68b M. Cano Bret,59c J. Cantero,128 T. Cao,160 Y. Cao,172 M. D. M. Capeans Garrido,36 I. Caprini,27b M. Caprini,27b M. Capua,41b,41a R. M. Carbone,39 R. Cardarelli,72a F. C. Cardillo,148 I. Carli,142 T. Carli,36 G. Carlino,68a B. T. Carlson,138 L. Carminati,67a,67b R. M. D. Carney,44a,44b S. Caron,118 E. Carquin,146b S. Carrá,67a,67b G. D. Carrillo-Montoya,36 D. Casadei,33b M. P. Casado,14,i A. F. Casha,166 D. W. Casper,170 R. Castelijn,119 F. L. Castillo,173 V. Castillo Gimenez,173 N. F. Castro,139a,139e A. Catinaccio,36 161801-9 PHYSICAL REVIEW LETTERS 123, 161801 (2019) J. R. Catmore,133 A. Cattai,36 J. Caudron,24 V. Cavaliere,29 E. Cavallaro,14 D. Cavalli,67a M. Cavalli-Sforza,14 V. Cavasinni,70a,70b E. Celebi,12b F. Ceradini,73a,73b L. Cerda Alberich,173 A. S. Cerqueira,79a A. Cerri,155 L. Cerrito,72a,72b F. Cerutti,18 A. Cervelli,23b,23a S. A. Cetin,12b A. Chafaq,35a D. Chakraborty,120 S. K. Chan,58 W. S. Chan,119 Y. L. Chan,62a J. D. Chapman,32 B. Chargeishvili,158b D. G. Charlton,21 C. C. Chau,34 C. A. Chavez Barajas,155 S. Che,125 A. Chegwidden,105 S. Chekanov,6 S. V. Chekulaev,167a G. A. Chelkov,78,j M. A. Chelstowska,36 C. Chen,59a C. H. Chen,77 H. Chen,29 J. Chen,59a J. Chen,39 S. Chen,136 S. J. Chen,15c X. Chen,15b,k Y. Chen,81 Y-H. Chen,45 H. C. Cheng,104 H. J. Cheng,15a,15d A. Cheplakov,78 E. Cheremushkina,122 R. Cherkaoui El Moursli,35e E. Cheu,7 K. Cheung,63 L. Chevalier,144 V. Chiarella,50 G. Chiarelli,70a G. Chiodini,66a A. S. Chisholm,36,21 A. Chitan,27b I. Chiu,162 Y. H. Chiu,175 M. V. Chizhov,78 K. Choi,64 A. R. Chomont,131 S. Chouridou,161 Y. S. Chow,119 V. Christodoulou,93 M. C. Chu,62a J. Chudoba,140 A. J. Chuinard,102 J. J. Chwastowski,83 L. Chytka,129 D. Cinca,46 V. Cindro,90 I. A. Cioară,24 A. Ciocio,18 F. Cirotto,68a,68b Z. H. Citron,179 M. Citterio,67a A. Clark,53 M. R. Clark,39 P. J. Clark,49 C. Clement,44a,44b Y. Coadou,100 M. Cobal,65a,65c A. Coccaro,54b J. Cochran,77 H. Cohen,160 A. E. C. Coimbra,179 L. Colasurdo,118 B. Cole,39 A. P. Colijn,119 J. Collot,57 P. Conde Muiño,139a E. Coniavitis,51 S. H. Connell,33b I. A. Connelly,99 S. Constantinescu,27b F. Conventi,68a,l A. M. Cooper-Sarkar,134 F. Cormier,174 K. J. R. Cormier,166 L. D. Corpe,93 M. Corradi,71a,71b E. E. Corrigan,95 F. Corriveau,102,m A. Cortes-Gonzalez,36 M. J. Costa,173 F. Costanza,5 D. Costanzo,148 G. Cottin,32 G. Cowan,92 B. E. Cox,99 J. Crane,99 K. Cranmer,123 S. J. Crawley,56 R. A. Creager,136 G. Cree,34 S. Crépé-Renaudin,57 F. Crescioli,135 M. Cristinziani,24 V. Croft,123 G. Crosetti,41b,41a A. Cueto,97 T. Cuhadar Donszelmann,148 A. R. Cukierman,152 S. Czekierda,83 P. Czodrowski,36 M. J. Da Cunha Sargedas De Sousa,59b C. Da Via,99 W. Dabrowski,82a T. Dado,28a,n S. Dahbi,35e T. Dai,104 F. Dallaire,108 C. Dallapiccola,101 M. Dam,40 G. D’amen,23b,23a J. Damp,98 J. R. Dandoy,136 M. F. Daneri,30 N. P. Dang,180 N. D Dann,99 M. Danninger,174 V. Dao,36 G. Darbo,54b S. Darmora,8 O. Dartsi,5 A. Dattagupta,130 T. Daubney,45 S. D’Auria,67a,67b W. Davey,24 C. David,45 T. Davidek,142 D. R. Davis,48 E. Dawe,103 I. Dawson,148 K. De,8 R. De Asmundis,68a A. De Benedetti,127 M. De Beurs,119 S. De Castro,23b,23a S. De Cecco,71a,71b N. De Groot,118 P. de Jong,119 H. De la Torre,105 F. De Lorenzi,77 A. De Maria,70a,70b D. De Pedis,71a A. De Salvo,71a U. De Sanctis,72a,72b M. De Santis,72a,72b A. De Santo,155 K. De Vasconcelos Corga,100 J. B. De Vivie De Regie,131 C. Debenedetti,145 D. V. Dedovich,78 N. Dehghanian,3 A. M. Deiana,104 M. Del Gaudio,41b,41a J. Del Peso,97 Y. Delabat Diaz,45 D. Delgove,131 F. Deliot,144 C. M. Delitzsch,7 M. Della Pietra,68a,68b D. Della Volpe,53 A. Dell’Acqua,36 L. Dell’Asta,25 M. Delmastro,5 C. Delporte,131 P. A. Delsart,57 D. A. DeMarco,166 S. Demers,182 M. Demichev,78 S. P. Denisov,122 D. Denysiuk,119 L. D’Eramo,135 D. Derendarz,83 J. E. Derkaoui,35d F. Derue,135 P. Dervan,89 K. Desch,24 C. Deterre,45 K. Dette,166 M. R. Devesa,30 P. O. Deviveiros,36 A. Dewhurst,143 S. Dhaliwal,26 F. A. Di Bello,53 A. Di Ciaccio,72a,72b L. Di Ciaccio,5 W. K. Di Clemente,136 C. Di Donato,68a,68b A. Di Girolamo,36 G. Di Gregorio,70a,70b B. Di Micco,73a,73b R. Di Nardo,101 K. F. Di Petrillo,58 R. Di Sipio,166 D. Di Valentino,34 C. Diaconu,100 M. Diamond,166 F. A. Dias,40 T. Dias Do Vale,139a M. A. Diaz,146a J. Dickinson,18 E. B. Diehl,104 J. Dietrich,19 S. Díez Cornell,45 A. Dimitrievska,18 J. Dingfelder,24 F. Dittus,36 F. Djama,100 T. Djobava,158b J. I. Djuvsland,60a M. A. B. Do Vale,79c M. Dobre,27b D. Dodsworth,26 C. Doglioni,95 J. Dolejsi,142 Z. Dolezal,142 M. Donadelli,79d J. Donini,38 A. D’onofrio,91 M. D’Onofrio,89 J. Dopke,143 A. Doria,68a M. T. Dova,87 A. T. Doyle,56 E. Drechsler,52 E. Dreyer,151 T. Dreyer,52 Y. Du,59b F. Dubinin,109 M. Dubovsky,28a A. Dubreuil,53 E. Duchovni,179 G. Duckeck,113 A. Ducourthial,135 O. A. Ducu,108,o D. Duda,114 A. Dudarev,36 A. C. Dudder,98 E. M. Duffield,18 L. Duflot,131 M. Dührssen,36 C. Dülsen,181 M. Dumancic,179 A. E. Dumitriu,27b,p A. K. Duncan,56 M. Dunford,60a A. Duperrin,100 H. Duran Yildiz,4a M. Düren,55 A. Durglishvili,158b D. Duschinger,47 B. Dutta,45 D. Duvnjak,1 M. Dyndal,45 S. Dysch,99 B. S. Dziedzic,83 C. Eckardt,45 K. M. Ecker,114 R. C. Edgar,104 T. Eifert,36 G. Eigen,17 K. Einsweiler,18 T. Ekelof,171 M. El Kacimi,35c R. El Kosseifi,100 V. Ellajosyula,100 M. Ellert,171 F. Ellinghaus,181 A. A. Elliot,91 N. Ellis,36 J. Elmsheuser,29 M. Elsing,36 D. Emeliyanov,143 A. Emerman,39 Y. Enari,162 J. S. Ennis,177 M. B. Epland,48 J. Erdmann,46 A. Ereditato,20 S. Errede,172 M. Escalier,131 C. Escobar,173 O. Estrada Pastor,173 A. I. Etienvre,144 E. Etzion,160 H. Evans,64 A. Ezhilov,137 M. Ezzi,35e F. Fabbri,56 L. Fabbri,23b,23a V. Fabiani,118 G. Facini,93 R. M. Faisca Rodrigues Pereira,139a R. M. Fakhrutdinov,122 S. Falciano,71a P. J. Falke,5 S. Falke,5 J. Faltova,142 Y. Fang,15a M. Fanti,67a,67b A. Farbin,8 A. Farilla,73a E. M. Farina,69a,69b T. Farooque,105 S. Farrell,18 S. M. Farrington,177 P. Farthouat,36 F. Fassi,35e P. Fassnacht,36 D. Fassouliotis,9 M. Faucci Giannelli,49 A. Favareto,54b,54a W. J. Fawcett,32 L. Fayard,131 O. L. Fedin,137,q W. Fedorko,174 M. Feickert,42 S. Feigl,133 L. Feligioni,100 C. Feng,59b E. J. Feng,36 M. Feng,48 M. J. Fenton,56 A. B. Fenyuk,122 L. Feremenga,8 J. Ferrando,45 A. Ferrari,171 P. Ferrari,119 R. Ferrari,69a D. E. Ferreira de Lima,60b A. Ferrer,173 D. Ferrere,53 C. Ferretti,104 F. Fiedler,98 A. Filipčič,90 F. Filthaut,118 161801-10 PHYSICAL REVIEW LETTERS 123, 161801 (2019) K. D. Finelli,25 M. C. N. Fiolhais,139a,139c,r L. Fiorini,173 C. Fischer,14 W. C. Fisher,105 N. Flaschel,45 I. Fleck,150 P. Fleischmann,104 R. R. M. Fletcher,136 T. Flick,181 B. M. Flierl,113 L. F. Flores,136 L. R. Flores Castillo,62a F. M. Follega,74a,74b N. Fomin,17 G. T. Forcolin,74a,74b A. Formica,144 F. A. Förster,14 A. C. Forti,99 A. G. Foster,21 D. Fournier,131 H. Fox,88 S. Fracchia,148 P. Francavilla,70a,70b M. Franchini,23b,23a S. Franchino,60a D. Francis,36 L. Franconi,145 M. Franklin,58 M. Frate,170 M. Fraternali,69a,69b A. N. Fray,91 D. Freeborn,93 S. M. Fressard-Batraneanu,36 B. Freund,108 W. S. Freund,79b E. M. Freundlich,46 D. C. Frizzell,127 D. Froidevaux,36 J. A. Frost,134 C. Fukunaga,163 E. Fullana Torregrosa,173 T. Fusayasu,115 J. Fuster,173 O. Gabizon,159 A. Gabrielli,23b,23a A. Gabrielli,18 G. P. Gach,82a S. Gadatsch,53 P. Gadow,114 G. Gagliardi,54b,54a L. G. Gagnon,108 C. Galea,27b B. Galhardo,139a,139c E. J. Gallas,134 B. J. Gallop,143 P. Gallus,141 G. Galster,40 R. Gamboa Goni,91 K. K. Gan,125 S. Ganguly,179 J. Gao,59a Y. Gao,89 Y. S. Gao,31,g C. García,173 J. E. García Navarro,173 J. A. García Pascual,15a M. Garcia-Sciveres,18 R. W. Gardner,37 N. Garelli,152 V. Garonne,133 K. Gasnikova,45 A. Gaudiello,54b,54a G. Gaudio,69a I. L. Gavrilenko,109 A. Gavrilyuk,110 C. Gay,174 G. Gaycken,24 E. N. Gazis,10 C. N. P. Gee,143 J. Geisen,52 M. Geisen,98 M. P. Geisler,60a K. Gellerstedt,44a,44b C. Gemme,54b M. H. Genest,57 C. Geng,104 S. Gentile,71a,71b S. George,92 D. Gerbaudo,14 G. Gessner,46 S. Ghasemi,150 M. Ghasemi Bostanabad,175 M. Ghneimat,24 B. Giacobbe,23b S. Giagu,71a,71b N. Giangiacomi,23b,23a P. Giannetti,70a A. Giannini,68a,68b S. M. Gibson,92 M. Gignac,145 D. Gillberg,34 G. Gilles,181 D. M. Gingrich,3,d M. P. Giordani,65a,65c F. M. Giorgi,23b P. F. Giraud,144 P. Giromini,58 G. Giugliarelli,65a,65c D. Giugni,67a F. Giuli,134 M. Giulini,60b S. Gkaitatzis,161 I. Gkialas,9,s E. L. Gkougkousis,14 P. Gkountoumis,10 L. K. Gladilin,112 C. Glasman,97 J. Glatzer,14 P. C. F. Glaysher,45 A. Glazov,45 M. Goblirsch-Kolb,26 J. Godlewski,83 S. Goldfarb,103 T. Golling,53 D. Golubkov,122 A. Gomes,139a,139b R. Goncalves Gama,79a R. Gonçalo,139a G. Gonella,51 L. Gonella,21 A. Gongadze,78 F. Gonnella,21 J. L. Gonski,58 S. González de la Hoz,173 S. Gonzalez-Sevilla,53 L. Goossens,36 P. A. Gorbounov,110 H. A. Gordon,29 B. Gorini,36 E. Gorini,66a,66b A. Gorišek,90 A. T. Goshaw,48 C. Gössling,46 M. I. Gostkin,78 C. A. Gottardo,24 C. R. Goudet,131 D. Goujdami,35c A. G. Goussiou,147 N. Govender,33b,t C. Goy,5 E. Gozani,159 I. Grabowska-Bold,82a P. O. J. Gradin,171 E. C. Graham,89 J. Gramling,170 E. Gramstad,133 S. Grancagnolo,19 V. Gratchev,137 P. M. Gravila,27f F. G. Gravili,66a,66b C. Gray,56 H. M. Gray,18 Z. D. Greenwood,94 C. Grefe,24 K. Gregersen,95 I. M. Gregor,45 P. Grenier,152 K. Grevtsov,45 N. A. Grieser,127 J. Griffiths,8 A. A. Grillo,145 K. Grimm,31,u S. Grinstein,14,v Ph. Gris,38 J.-F. Grivaz,131 S. Groh,98 E. Gross,179 J. Grosse-Knetter,52 G. C. Grossi,94 Z. J. Grout,93 C. Grud,104 A. Grummer,117 L. Guan,104 W. Guan,180 J. Guenther,36 A. Guerguichon,131 F. Guescini,167a D. Guest,170 R. Gugel,51 B. Gui,125 T. Guillemin,5 S. Guindon,36 U. Gul,56 C. Gumpert,36 J. Guo,59c W. Guo,104 Y. Guo,59a,w Z. Guo,100 R. Gupta,45 S. Gurbuz,12c G. Gustavino,127 B. J. Gutelman,159 P. Gutierrez,127 C. Gutschow,93 C. Guyot,144 M. P. Guzik,82a C. Gwenlan,134 C. B. Gwilliam,89 A. Haas,123 C. Haber,18 H. K. Hadavand,8 N. Haddad,35e A. Hadef,59a S. Hageböck,24 M. Hagihara,168 H. Hakobyan,183,a M. Haleem,176 J. Haley,128 G. Halladjian,105 G. D. Hallewell,100 K. Hamacher,181 P. Hamal,129 K. Hamano,175 A. Hamilton,33a G. N. Hamity,148 K. Han,59a,x L. Han,59a S. Han,15a,15d K. Hanagaki,80,y M. Hance,145 D. M. Handl,113 B. Haney,136 R. Hankache,135 P. Hanke,60a E. Hansen,95 J. B. Hansen,40 J. D. Hansen,40 M. C. Hansen,24 P. H. Hansen,40 E. C. Hanson,99 K. Hara,168 A. S. Hard,180 T. Harenberg,181 S. Harkusha,106 P. F. Harrison,177 N. M. Hartmann,113 Y. Hasegawa,149 A. Hasib,49 S. Hassani,144 S. Haug,20 R. Hauser,105 L. Hauswald,47 L. B. Havener,39 M. Havranek,141 C. M. Hawkes,21 R. J. Hawkings,36 D. Hayden,105 C. Hayes,154 C. P. Hays,134 J. M. Hays,91 H. S. Hayward,89 S. J. Haywood,143 M. P. Heath,49 V. Hedberg,95 L. Heelan,8 S. Heer,24 K. K. Heidegger,51 J. Heilman,34 S. Heim,45 T. Heim,18 B. Heinemann,45,z J. J. Heinrich,113 L. Heinrich,123 C. Heinz,55 J. Hejbal,140 L. Helary,36 A. Held,174 S. Hellesund,133 S. Hellman,44a,44b C. Helsens,36 R. C. W. Henderson,88 Y. Heng,180 S. Henkelmann,174 A. M. Henriques Correia,36 G. H. Herbert,19 H. Herde,26 V. Herget,176 Y. Hernández Jiménez,33c H. Herr,98 M. G. Herrmann,113 T. Herrmann,47 G. Herten,51 R. Hertenberger,113 L. Hervas,36 T. C. Herwig,136 G. G. Hesketh,93 N. P. Hessey,167a A. Higashida,162 S. Higashino,80 E. Higón-Rodriguez,173 K. Hildebrand,37 E. Hill,175 J. C. Hill,32 K. K. Hill,29 K. H. Hiller,45 S. J. Hillier,21 M. Hils,47 I. Hinchliffe,18 M. Hirose,132 D. Hirschbuehl,181 B. Hiti,90 O. Hladik,140 D. R. Hlaluku,33c X. Hoad,49 J. Hobbs,154 N. Hod,167a M. C. Hodgkinson,148 A. Hoecker,36 M. R. Hoeferkamp,117 F. Hoenig,113 D. Hohn,24 D. Hohov,131 T. R. Holmes,37 M. Holzbock,113 M. Homann,46 S. Honda,168 T. Honda,80 T. M. Hong,138 A. Hönle,114 B. H. Hooberman,172 W. H. Hopkins,130 Y. Horii,116 P. Horn,47 A. J. Horton,151 L. A. Horyn,37 J-Y. Hostachy,57 A. Hostiuc,147 S. Hou,157 A. Hoummada,35a J. Howarth,99 J. Hoya,87 M. Hrabovsky,129 J. Hrdinka,36 I. Hristova,19 J. Hrivnac,131 A. Hrynevich,107 T. Hryn’ova,5 P. J. Hsu,63 S.-C. Hsu,147 Q. Hu,29 S. Hu,59c Y. Huang,15a Z. Hubacek,141 F. Hubaut,100 M. Huebner,24 F. Huegging,24 T. B. Huffman,134 M. Huhtinen,36 R. F. H. Hunter,34 P. Huo,154 A. M. Hupe,34 N. Huseynov,78,c J. Huston,105 J. Huth,58 R. Hyneman,104 G. Iacobucci,53 161801-11 PHYSICAL REVIEW LETTERS 123, 161801 (2019) G. Iakovidis,29 I. Ibragimov,150 L. Iconomidou-Fayard,131 Z. Idrissi,35e P. I. Iengo,36 R. Ignazzi,40 O. Igonkina,119,a,aa R. Iguchi,162 T. Iizawa,53 Y. Ikegami,80 M. Ikeno,80 D. Iliadis,161 N. Ilic,118 F. Iltzsche,47 G. Introzzi,69a,69b M. Iodice,73a K. Iordanidou,39 V. Ippolito,71a,71b M. F. Isacson,171 N. Ishijima,132 M. Ishino,162 M. Ishitsuka,164 W. Islam,128 C. Issever,134 S. Istin,159 F. Ito,168 J. M. Iturbe Ponce,62a R. Iuppa,74a,74b A. Ivina,179 H. Iwasaki,80 J. M. Izen,43 V. Izzo,68a P. Jacka,140 P. Jackson,1 R. M. Jacobs,24 V. Jain,2 G. Jäkel,181 K. B. Jakobi,98 K. Jakobs,51 S. Jakobsen,75 T. Jakoubek,140 D. O. Jamin,128 R. Jansky,53 J. Janssen,24 M. Janus,52 P. A. Janus,82a G. Jarlskog,95 N. Javadov,78,c T. Javůrek,36 M. Javurkova,51 F. Jeanneau,144 L. Jeanty,18 J. Jejelava,158a,bb A. Jelinskas,177 P. Jenni,51,cc J. Jeong,45 N. Jeong,45 S. Jézéquel,5 H. Ji,180 J. Jia,154 H. Jiang,77 Y. Jiang,59a Z. Jiang,152 S. Jiggins,51 F. A. Jimenez Morales,38 J. Jimenez Pena,173 S. Jin,15c A. Jinaru,27b O. Jinnouchi,164 H. Jivan,33c P. Johansson,148 K. A. Johns,7 C. A. Johnson,64 W. J. Johnson,147 K. Jon-And,44a,44b R. W. L. Jones,88 S. D. Jones,155 S. Jones,7 T. J. Jones,89 J. Jongmanns,60a P. M. Jorge,139a,139b J. Jovicevic,167a X. Ju,18 J. J. Junggeburth,114 A. Juste Rozas,14,v A. Kaczmarska,83 M. Kado,131 H. Kagan,125 M. Kagan,152 T. Kaji,178 E. Kajomovitz,159 C. W. Kalderon,95 A. Kaluza,98 S. Kama,42 A. Kamenshchikov,122 L. Kanjir,90 Y. Kano,162 V. A. Kantserov,111 J. Kanzaki,80 B. Kaplan,123 L. S. Kaplan,180 D. Kar,33c M. J. Kareem,167b E. Karentzos,10 S. N. Karpov,78 Z. M. Karpova,78 V. Kartvelishvili,88 A. N. Karyukhin,122 L. Kashif,180 R. D. Kass,125 A. Kastanas,44a,44b Y. Kataoka,162 C. Kato,59d,59c J. Katzy,45 K. Kawade,81 K. Kawagoe,86 T. Kawamoto,162 G. Kawamura,52 E. F. Kay,89 V. F. Kazanin,121b,121a R. Keeler,175 R. Kehoe,42 J. S. Keller,34 E. Kellermann,95 J. J. Kempster,21 J. Kendrick,21 O. Kepka,140 S. Kersten,181 B. P. Kerševan,90 S. Ketabchi Haghighat,166 R. A. Keyes,102 M. Khader,172 F. Khalil-Zada,13 A. Khanov,128 A. G. Kharlamov,121b,121a T. Kharlamova,121b,121a E. E. Khoda,174 A. Khodinov,165 T. J. Khoo,53 E. Khramov,78 J. Khubua,158b S. Kido,81 M. Kiehn,53 C. R. Kilby,92 Y. K. Kim,37 N. Kimura,65a,65c O. M. Kind,19 B. T. King,89,a D. Kirchmeier,47 J. Kirk,143 A. E. Kiryunin,114 T. Kishimoto,162 D. Kisielewska,82a V. Kitali,45 O. Kivernyk,5 E. Kladiva,28b,a T. Klapdor-Kleingrothaus,51 M. H. Klein,104 M. Klein,89 U. Klein,89 K. Kleinknecht,98 P. Klimek,120 A. Klimentov,29 T. Klingl,24 T. Klioutchnikova,36 F. F. Klitzner,113 P. Kluit,119 S. Kluth,114 E. Kneringer,75 E. B. F. G. Knoops,100 A. Knue,51 A. Kobayashi,162 D. Kobayashi,86 T. Kobayashi,162 M. Kobel,47 M. Kocian,152 P. Kodys,142 P. T. Koenig,24 T. Koffas,34 E. Koffeman,119 N. M. Köhler,114 T. Koi,152 M. Kolb,60b I. Koletsou,5 T. Kondo,80 N. Kondrashova,59c K. Köneke,51 A. C. König,118 T. Kono,124 R. Konoplich,123,dd V. Konstantinides,93 N. Konstantinidis,93 B. Konya,95 R. Kopeliansky,64 S. Koperny,82a K. Korcyl,83 K. Kordas,161 G. Koren,160 A. Korn,93 I. Korolkov,14 E. V. Korolkova,148 N. Korotkova,112 O. Kortner,114 S. Kortner,114 T. Kosek,142 V. V. Kostyukhin,24 A. Kotwal,48 A. Koulouris,10 A. Kourkoumeli-Charalampidi,69a,69b C. Kourkoumelis,9 E. Kourlitis,148 V. Kouskoura,29 A. B. Kowalewska,83 R. Kowalewski,175 T. Z. Kowalski,82a C. Kozakai,162 W. Kozanecki,144 A. S. Kozhin,122 V. A. Kramarenko,112 G. Kramberger,90 D. Krasnopevtsev,59a M. W. Krasny,135 A. Krasznahorkay,36 D. Krauss,114 J. A. Kremer,82a J. Kretzschmar,89 P. Krieger,166 K. Krizka,18 K. Kroeninger,46 H. Kroha,114 J. Kroll,140 J. Kroll,136 J. Krstic,16 U. Kruchonak,78 H. Krüger,24 N. Krumnack,77 M. C. Kruse,48 T. Kubota,103 S. Kuday,4b J. T. Kuechler,181 S. Kuehn,36 A. Kugel,60a F. Kuger,176 T. Kuhl,45 V. Kukhtin,78 R. Kukla,100 Y. Kulchitsky,106 S. Kuleshov,146b Y. P. Kulinich,172 M. Kuna,57 T. Kunigo,84 A. Kupco,140 T. Kupfer,46 O. Kuprash,160 H. Kurashige,81 L. L. Kurchaninov,167a Y. A. Kurochkin,106 A. Kurova,111 M. G. Kurth,15a,15d E. S. Kuwertz,36 M. Kuze,164 J. Kvita,129 T. Kwan,102 A. La Rosa,114 J. L. La Rosa Navarro,79d L. La Rotonda,41b,41a F. La Ruffa,41b,41a C. Lacasta,173 F. Lacava,71a,71b J. Lacey,45 D. P. J. Lack,99 H. Lacker,19 D. Lacour,135 E. Ladygin,78 R. Lafaye,5 B. Laforge,135 T. Lagouri,33c S. Lai,52 S. Lammers,64 W. Lampl,7 E. Lançon,29 U. Landgraf,51 M. P. J. Landon,91 M. C. Lanfermann,53 V. S. Lang,45 J. C. Lange,52 R. J. Langenberg,36 A. J. Lankford,170 F. Lanni,29 K. Lantzsch,24 A. Lanza,69a A. Lapertosa,54b,54a S. Laplace,135 J. F. Laporte,144 T. Lari,67a F. Lasagni Manghi,23b,23a M. Lassnig,36 T. S. Lau,62a A. Laudrain,131 M. Lavorgna,68a,68b M. Lazzaroni,67a,67b B. Le,103 O. Le Dortz,135 E. Le Guirriec,100 E. P. Le Quilleuc,144 M. LeBlanc,7 T. LeCompte,6 F. Ledroit-Guillon,57 C. A. Lee,29 G. R. Lee,146a L. Lee,58 S. C. Lee,157 B. Lefebvre,102 M. Lefebvre,175 F. Legger,113 C. Leggett,18 K. Lehmann,151 N. Lehmann,181 G. Lehmann Miotto,36 W. A. Leight,45 A. Leisos,161,ee M. A. L. Leite,79d R. Leitner,142 D. Lellouch,179,a K. J. C. Leney,93 T. Lenz,24 B. Lenzi,36 R. Leone,7 S. Leone,70a C. Leonidopoulos,49 G. Lerner,155 C. Leroy,108 R. Les,166 A. A. J. Lesage,144 C. G. Lester,32 M. Levchenko,137 J. Levêque,5 D. Levin,104 L. J. Levinson,179 D. Lewis,91 B. Li,15b B. Li,104 C-Q. Li,59a,ff H. Li,59b L. Li,59c M. Li,15a Q. Li,15a,15d Q. Y. Li,59a S. Li,59d,59c X. Li,59c Y. Li,150 Z. Liang,15a B. Liberti,72a A. Liblong,166 K. Lie,62c S. Liem,119 A. Limosani,156 C. Y. Lin,32 K. Lin,105 T. H. Lin,98 R. A. Linck,64 J. H. Lindon,21 B. E. Lindquist,154 A. L. Lionti,53 E. Lipeles,136 A. Lipniacka,17 M. Lisovyi,60b T. M. Liss,172,gg A. Lister,174 A. M. Litke,145 J. D. Little,8 B. Liu,77 B. L Liu,6 H. B. Liu,29 H. Liu,104 J. B. Liu,59a J. K. K. Liu,134 K. Liu,135 M. Liu,59a 161801-12 PHYSICAL REVIEW LETTERS 123, 161801 (2019) P. Liu,18 Y. Liu,15a,15d Y. L. Liu,59a Y. W. Liu,59a M. Livan,69a,69b A. Lleres,57 J. Llorente Merino,15a S. L. Lloyd,91 C. Y. Lo,62b F. Lo Sterzo,42 E. M. Lobodzinska,45 P. Loch,7 T. Lohse,19 K. Lohwasser,148 M. Lokajicek,140 J. D. Long,172 R. E. Long,88 L. Longo,66a,66b K. A. Looper,125 J. A. Lopez,146b I. Lopez Paz,99 A. Lopez Solis,148 J. Lorenz,113 N. Lorenzo Martinez,5 M. Losada,22 P. J. Lösel,113 A. Lösle,51 X. Lou,45 X. Lou,15a A. Lounis,131 J. Love,6 P. A. Love,88 J. J. Lozano Bahilo,173 H. Lu,62a M. Lu,59a N. Lu,104 Y. J. Lu,63 H. J. Lubatti,147 C. Luci,71a,71b A. Lucotte,57 C. Luedtke,51 F. Luehring,64 I. Luise,135 L. Luminari,71a B. Lund-Jensen,153 M. S. Lutz,101 P. M. Luzi,135 D. Lynn,29 R. Lysak,140 E. Lytken,95 F. Lyu,15a V. Lyubushkin,78 T. Lyubushkina,78 H. Ma,29 L. L. Ma,59b Y. Ma,59b G. Maccarrone,50 A. Macchiolo,114 C. M. Macdonald,148 J. Machado Miguens,136,139b D. Madaffari,173 R. Madar,38 W. F. Mader,47 A. Madsen,45 N. Madysa,47 J. Maeda,81 K. Maekawa,162 S. Maeland,17 T. Maeno,29 M. Maerker,47 A. S. Maevskiy,112 V. Magerl,51 D. J. Mahon,39 C. Maidantchik,79b T. Maier,113 A. Maio,139a,139b,139d O. Majersky,28a S. Majewski,130 Y. Makida,80 N. Makovec,131 B. Malaescu,135 Pa. Malecki,83 V. P. Maleev,137 F. Malek,57 U. Mallik,76 D. Malon,6 C. Malone,32 S. Maltezos,10 S. Malyukov,36 J. Mamuzic,173 G. Mancini,50 I. Mandić,90 J. Maneira,139a L. Manhaes de Andrade Filho,79a J. Manjarres Ramos,47 K. H. Mankinen,95 A. Mann,113 A. Manousos,75 B. Mansoulie,144 J. D. Mansour,15a M. Mantoani,52 S. Manzoni,67a,67b A. Marantis,161 G. Marceca,30 L. March,53 L. Marchese,134 G. Marchiori,135 M. Marcisovsky,140 C. A. Marin Tobon,36 M. Marjanovic,38 D. E. Marley,104 F. Marroquim,79b Z. Marshall,18 M. U. F Martensson,171 S. Marti-Garcia,173 C. B. Martin,125 T. A. Martin,177 V. J. Martin,49 B. Martin dit Latour,17 M. Martinez,14,v V. I. Martinez Outschoorn,101 S. Martin-Haugh,143 V. S. Martoiu,27b A. C. Martyniuk,93 A. Marzin,36 L. Masetti,98 T. Mashimo,162 R. Mashinistov,109 J. Masik,99 A. L. Maslennikov,121b,121a L. H. Mason,103 L. Massa,72a,72b P. Massarotti,68a,68b P. Mastrandrea,5 A. Mastroberardino,41b,41a T. Masubuchi,162 P. Mättig,181 J. Maurer,27b B. Maček,90 S. J. Maxfield,89 D. A. Maximov,121b,121a R. Mazini,157 I. Maznas,161 S. M. Mazza,145 G. Mc Goldrick,166 S. P. Mc Kee,104 T. G. McCarthy,114 L. I. McClymont,93 E. F. McDonald,103 J. A. Mcfayden,36 M. A. McKay,42 K. D. McLean,175 S. J. McMahon,143 P. C. McNamara,103 C. J. McNicol,177 R. A. McPherson,175,m J. E. Mdhluli,33c Z. A. Meadows,101 S. Meehan,147 T. Megy,51 S. Mehlhase,113 A. Mehta,89 T. Meideck,57 B. Meirose,43 D. Melini,173,hh B. R. Mellado Garcia,33c J. D. Mellenthin,52 M. Melo,28a F. Meloni,45 A. Melzer,24 S. B. Menary,99 E. D. Mendes Gouveia,139a L. Meng,89 X. T. Meng,104 A. Mengarelli,23b,23a S. Menke,114 E. Meoni,41b,41a S. Mergelmeyer,19 S. A. M. Merkt,138 C. Merlassino,20 P. Mermod,53 L. Merola,68a,68b C. Meroni,67a F. S. Merritt,37 A. Messina,71a,71b J. Metcalfe,6 A. S. Mete,170 C. Meyer,136 J. Meyer,159 J-P. Meyer,144 H. Meyer Zu Theenhausen,60a F. Miano,155 R. P. Middleton,143 L. Mijović,49 G. Mikenberg,179 M. Mikestikova,140 M. Mikuž,90 M. Milesi,103 A. Milic,166 D. A. Millar,91 D. W. Miller,37 A. Milov,179 D. A. Milstead,44a,44b A. A. Minaenko,122 M. Miñano Moya,173 I. A. Minashvili,158b A. I. Mincer,123 B. Mindur,82a M. Mineev,78 Y. Minegishi,162 Y. Ming,180 L. M. Mir,14 A. Mirto,66a,66b K. P. Mistry,136 T. Mitani,178 J. Mitrevski,113 V. A. Mitsou,173 M. Mittal,59c A. Miucci,20 P. S. Miyagawa,148 A. Mizukami,80 J. U. Mjörnmark,95 T. Mkrtchyan,183 M. Mlynarikova,142 T. Moa,44a,44b K. Mochizuki,108 P. Mogg,51 S. Mohapatra,39 S. Molander,44a,44b R. Moles-Valls,24 M. C. Mondragon,105 K. Mönig,45 J. Monk,40 E. Monnier,100 A. Montalbano,151 J. Montejo Berlingen,36 F. Monticelli,87 S. Monzani,67a N. Morange,131 D. Moreno,22 M. Moreno Llácer,36 P. Morettini,54b M. Morgenstern,119 S. Morgenstern,47 D. Mori,151 M. Morii,58 M. Morinaga,178 V. Morisbak,133 A. K. Morley,36 G. Mornacchi,36 A. P. Morris,93 J. D. Morris,91 L. Morvaj,154 P. Moschovakos,10 M. Mosidze,158b H. J. Moss,148 J. Moss,31,ii K. Motohashi,164 R. Mount,152 E. Mountricha,36 E. J. W. Moyse,101 S. Muanza,100 F. Mueller,114 J. Mueller,138 R. S. P. Mueller,113 D. Muenstermann,88 G. A. Mullier,95 F. J. Munoz Sanchez,99 P. Murin,28b W. J. Murray,177,143 A. Murrone,67a,67b M. Muškinja,90 C. Mwewa,33a A. G. Myagkov,122,jj J. Myers,130 M. Myska,141 B. P. Nachman,18 O. Nackenhorst,46 K. Nagai,134 K. Nagano,80 Y. Nagasaka,61 M. Nagel,51 E. Nagy,100 A. M. Nairz,36 Y. Nakahama,116 K. Nakamura,80 T. Nakamura,162 I. Nakano,126 H. Nanjo,132 F. Napolitano,60a R. F. Naranjo Garcia,45 R. Narayan,11 D. I. Narrias Villar,60a I. Naryshkin,137 T. Naumann,45 G. Navarro,22 R. Nayyar,7 H. A. Neal,104,a P. Y. Nechaeva,109 T. J. Neep,144 A. Negri,69a,69b M. Negrini,23b S. Nektarijevic,118 C. Nellist,52 M. E. Nelson,134 S. Nemecek,140 P. Nemethy,123 M. Nessi,36,kk M. S. Neubauer,172 M. Neumann,181 P. R. Newman,21 T. Y. Ng,62c Y. S. Ng,19 H. D. N. Nguyen,100 T. Nguyen Manh,108 E. Nibigira,38 R. B. Nickerson,134 R. Nicolaidou,144 D. S. Nielsen,40 J. Nielsen,145 N. Nikiforou,11 V. Nikolaenko,122,jj I. Nikolic-Audit,135 K. Nikolopoulos,21 P. Nilsson,29 Y. Ninomiya,80 A. Nisati,71a N. Nishu,59c R. Nisius,114 I. Nitsche,46 T. Nitta,178 T. Nobe,162 Y. Noguchi,84 M. Nomachi,132 I. Nomidis,135 M. A. Nomura,29 T. Nooney,91 M. Nordberg,36 N. Norjoharuddeen,134 T. Novak,90 O. Novgorodova,47 R. Novotny,141 L. Nozka,129 K. Ntekas,170 E. Nurse,93 F. Nuti,103 F. G. Oakham,34,d H. Oberlack,114 J. Ocariz,135 A. Ochi,81 I. Ochoa,39 J. P. Ochoa-Ricoux,146a K. O’Connor,26 S. Oda,86 S. Odaka,80 S. Oerdek,52 A. Oh,99 161801-13 PHYSICAL REVIEW LETTERS 123, 161801 (2019) S. H. Oh,48 C. C. Ohm,153 H. Oide,54b,54a M. L. Ojeda,166 H. Okawa,168 Y. Okazaki,84 Y. Okumura,162 T. Okuyama,80 A. Olariu,27b L. F. Oleiro Seabra,139a S. A. Olivares Pino,146a D. Oliveira Damazio,29 J. L. Oliver,1 M. J. R. Olsson,37 A. Olszewski,83 J. Olszowska,83 D. C. O’Neil,151 A. Onofre,139a,139e K. Onogi,116 P. U. E. Onyisi,11 H. Oppen,133 M. J. Oreglia,37 G. E. Orellana,87 Y. Oren,160 D. Orestano,73a,73b N. Orlando,62b A. A. O’Rourke,45 R. S. Orr,166 B. Osculati,54b,54a,a V. O’Shea,56 R. Ospanov,59a G. Otero y Garzon,30 H. Otono,86 M. Ouchrif,35d F. Ould-Saada,133 A. Ouraou,144 Q. Ouyang,15a M. Owen,56 R. E. Owen,21 V. E. Ozcan,12c N. Ozturk,8 J. Pacalt,129 H. A. Pacey,32 K. Pachal,151 A. Pacheco Pages,14 L. Pacheco Rodriguez,144 C. Padilla Aranda,14 S. Pagan Griso,18 M. Paganini,182 G. Palacino,64 S. Palazzo,49 S. Palestini,36 M. Palka,82b D. Pallin,38 I. Panagoulias,10 C. E. Pandini,36 J. G. Panduro Vazquez,92 P. Pani,36 G. Panizzo,65a,65c L. Paolozzi,53 T. D. Papadopoulou,10 K. Papageorgiou,9,s A. Paramonov,6 D. Paredes Hernandez,62b S. R. Paredes Saenz,134 B. Parida,165 T. H. Park,34 A. J. Parker,88 K. A. Parker,45 M. A. Parker,32 F. Parodi,54b,54a J. A. Parsons,39 U. Parzefall,51 V. R. Pascuzzi,166 J. M. P. Pasner,145 E. Pasqualucci,71a S. Passaggio,54b F. Pastore,92 P. Pasuwan,44a,44b S. Pataraia,98 J. R. Pater,99 A. Pathak,180 T. Pauly,36 B. Pearson,114 M. Pedersen,133 L. Pedraza Diaz,118 R. Pedro,139a,139b S. V. Peleganchuk,121b,121a O. Penc,140 C. Peng,15a H. Peng,59a B. S. Peralva,79a M. M. Perego,131 A. P. Pereira Peixoto,139a D. V. Perepelitsa,29 F. Peri,19 L. Perini,67a,67b H. Pernegger,36 S. Perrella,68a,68b V. D. Peshekhonov,78,a K. Peters,45 R. F. Y. Peters,99 B. A. Petersen,36 T. C. Petersen,40 E. Petit,57 A. Petridis,1 C. Petridou,161 P. Petroff,131 M. Petrov,134 F. Petrucci,73a,73b M. Pettee,182 N. E. Pettersson,101 A. Peyaud,144 R. Pezoa,146b T. Pham,103 F. H. Phillips,105 P. W. Phillips,143 M. W. Phipps,172 G. Piacquadio,154 E. Pianori,18 A. Picazio,101 M. A. Pickering,134 R. H. Pickles,99 R. Piegaia,30 J. E. Pilcher,37 A. D. Pilkington,99 M. Pinamonti,72a,72b J. L. Pinfold,3 M. Pitt,179 L. Pizzimento,72a,72b M.-A. Pleier,29 V. Pleskot,142 E. Plotnikova,78 D. Pluth,77 P. Podberezko,121b,121a R. Poettgen,95 R. Poggi,53 L. Poggioli,131 I. Pogrebnyak,105 D. Pohl,24 I. Pokharel,52 G. Polesello,69a A. Poley,18 A. Policicchio,71a,71b R. Polifka,36 A. Polini,23b C. S. Pollard,45 V. Polychronakos,29 D. Ponomarenko,111 L. Pontecorvo,36 G. A. Popeneciu,27d D. M. Portillo Quintero,135 S. Pospisil,141 K. Potamianos,45 I. N. Potrap,78 C. J. Potter,32 H. Potti,11 T. Poulsen,95 J. Poveda,36 T. D. Powell,148 M. E. Pozo Astigarraga,36 P. Pralavorio,100 S. Prell,77 D. Price,99 M. Primavera,66a S. Prince,102 N. Proklova,111 K. Prokofiev,62c F. Prokoshin,146b S. Protopopescu,29 J. Proudfoot,6 M. Przybycien,82a A. Puri,172 P. Puzo,131 J. Qian,104 Y. Qin,99 A. Quadt,52 M. Queitsch-Maitland,45 A. Qureshi,1 P. Rados,103 F. Ragusa,67a,67b G. Rahal,96 J. A. Raine,53 S. Rajagopalan,29 A. Ramirez Morales,91 T. Rashid,131 S. Raspopov,5 M. G. Ratti,67a,67b D. M. Rauch,45 F. Rauscher,113 S. Rave,98 B. Ravina,148 I. Ravinovich,179 J. H. Rawling,99 M. Raymond,36 A. L. Read,133 N. P. Readioff,57 M. Reale,66a,66b D. M. Rebuzzi,69a,69b A. Redelbach,176 G. Redlinger,29 R. Reece,145 R. G. Reed,33c K. Reeves,43 L. Rehnisch,19 J. Reichert,136 D. Reikher,160 A. Reiss,98 C. Rembser,36 H. Ren,15a M. Rescigno,71a S. Resconi,67a E. D. Resseguie,136 S. Rettie,174 E. Reynolds,21 O. L. Rezanova,121b,121a P. Reznicek,142 E. Ricci,74a,74b R. Richter,114 S. Richter,45 E. Richter-Was,82b O. Ricken,24 M. Ridel,135 P. Rieck,114 C. J. Riegel,181 O. Rifki,45 M. Rijssenbeek,154 A. Rimoldi,69a,69b M. Rimoldi,20 L. Rinaldi,23b G. Ripellino,153 B. Ristić,88 E. Ritsch,36 I. Riu,14 J. C. Rivera Vergara,146a F. Rizatdinova,128 E. Rizvi,91 C. Rizzi,14 R. T. Roberts,99 S. H. Robertson,102,m D. Robinson,32 J. E. M. Robinson,45 A. Robson,56 E. Rocco,98 C. Roda,70a,70b Y. Rodina,100 S. Rodriguez Bosca,173 A. Rodriguez Perez,14 D. Rodriguez Rodriguez,173 A. M. Rodríguez Vera,167b S. Roe,36 C. S. Rogan,58 O. Røhne,133 R. Röhrig,114 C. P. A. Roland,64 J. Roloff,58 A. Romaniouk,111 M. Romano,23b,23a N. Rompotis,89 M. Ronzani,123 L. Roos,135 S. Rosati,71a K. Rosbach,51 N-A. Rosien,52 B. J. Rosser,136 E. Rossi,45 E. Rossi,73a,73b E. Rossi,68a,68b L. P. Rossi,54b L. Rossini,67a,67b J. H. N. Rosten,32 R. Rosten,14 M. Rotaru,27b J. Rothberg,147 D. Rousseau,131 D. Roy,33c A. Rozanov,100 Y. Rozen,159 X. Ruan,33c F. Rubbo,152 F. Rühr,51 A. Ruiz-Martinez,173 Z. Rurikova,51 N. A. Rusakovich,78 H. L. Russell,102 J. P. Rutherfoord,7 E. M. Rüttinger,45,ll Y. F. Ryabov,137 M. Rybar,172 G. Rybkin,131 S. Ryu,6 A. Ryzhov,122 G. F. Rzehorz,52 P. Sabatini,52 G. Sabato,119 S. Sacerdoti,131 H. F-W. Sadrozinski,145 R. Sadykov,78 F. Safai Tehrani,71a P. Saha,120 M. Sahinsoy,60a A. Sahu,181 M. Saimpert,45 M. Saito,162 T. Saito,162 H. Sakamoto,162 A. Sakharov,123,dd D. Salamani,53 G. Salamanna,73a,73b J. E. Salazar Loyola,146b P. H. Sales De Bruin,171 D. Salihagic,114,a A. Salnikov,152 J. Salt,173 D. Salvatore,41b,41a F. Salvatore,155 A. Salvucci,62a,62c A. Salzburger,36 J. Samarati,36 D. Sammel,51 D. Sampsonidis,161 D. Sampsonidou,161 J. Sánchez,173 A. Sanchez Pineda,65a,65c H. Sandaker,133 C. O. Sander,45 M. Sandhoff,181 C. Sandoval,22 D. P. C. Sankey,143 M. Sannino,54b,54a Y. Sano,116 A. Sansoni,50 C. Santoni,38 H. Santos,139a I. Santoyo Castillo,155 A. Santra,173 A. Sapronov,78 J. G. Saraiva,139a,139d O. Sasaki,80 K. Sato,168 E. Sauvan,5 P. Savard,166,d N. Savic,114 R. Sawada,162 C. Sawyer,143 L. Sawyer,94,mm C. Sbarra,23b A. Sbrizzi,23a T. Scanlon,93 J. Schaarschmidt,147 P. Schacht,114 B. M. Schachtner,113 D. Schaefer,37 L. Schaefer,136 J. Schaeffer,98 S. Schaepe,36 U. Schäfer,98 A. C. Schaffer,131 161801-14 PHYSICAL REVIEW LETTERS 123, 161801 (2019) D. Schaile,113 R. D. Schamberger,154 N. Scharmberg,99 V. A. Schegelsky,137 D. Scheirich,142 F. Schenck,19 M. Schernau,170 C. Schiavi,54b,54a S. Schier,145 L. K. Schildgen,24 Z. M. Schillaci,26 E. J. Schioppa,36 M. Schioppa,41b,41a K. E. Schleicher,51 S. Schlenker,36 K. R. Schmidt-Sommerfeld,114 K. Schmieden,36 C. Schmitt,98 S. Schmitt,45 S. Schmitz,98 J. C. Schmoeckel,45 U. Schnoor,51 L. Schoeffel,144 A. Schoening,60b E. Schopf,134 M. Schott,98 J. F. P. Schouwenberg,118 J. Schovancova,36 S. Schramm,53 A. Schulte,98 H-C. Schultz-Coulon,60a M. Schumacher,51 B. A. Schumm,145 Ph. Schune,144 A. Schwartzman,152 T. A. Schwarz,104 Ph. Schwemling,144 R. Schwienhorst,105 A. Sciandra,24 G. Sciolla,26 M. Scornajenghi,41b,41a F. Scuri,70a F. Scutti,103 L. M. Scyboz,114 C. D. Sebastiani,71a,71b P. Seema,19 S. C. Seidel,117 A. Seiden,145 T. Seiss,37 J. M. Seixas,79b G. Sekhniaidze,68a K. Sekhon,104 S. J. Sekula,42 N. Semprini-Cesari,23b,23a S. Sen,48 S. Senkin,38 C. Serfon,133 L. Serin,131 L. Serkin,65a,65b M. Sessa,59a H. Severini,127 F. Sforza,169 A. Sfyrla,53 E. Shabalina,52 J. D. Shahinian,145 N. W. Shaikh,44a,44b L. Y. Shan,15a R. Shang,172 J. T. Shank,25 M. Shapiro,18 A. Sharma,134 A. S. Sharma,1 P. B. Shatalov,110 K. Shaw,155 S. M. Shaw,99 A. Shcherbakova,137 Y. Shen,127 N. Sherafati,34 A. D. Sherman,25 P. Sherwood,93 L. Shi,157,nn S. Shimizu,80 C. O. Shimmin,182 Y. Shimogama,178 M. Shimojima,115 I. P. J. Shipsey,134 S. Shirabe,86 M. Shiyakova,78 J. Shlomi,179 A. Shmeleva,109 D. Shoaleh Saadi,108 M. J. Shochet,37 S. Shojaii,103 D. R. Shope,127 S. Shrestha,125 E. Shulga,111 P. Sicho,140 A. M. Sickles,172 P. E. Sidebo,153 E. Sideras Haddad,33c O. Sidiropoulou,36 A. Sidoti,23b,23a F. Siegert,47 Dj. Sijacki,16 J. Silva,139a M. Silva Jr.,180 M. V. Silva Oliveira,79a S. B. Silverstein,44a S. Simion,131 E. Simioni,98 M. Simon,98 R. Simoniello,98 P. Sinervo,166 N. B. Sinev,130 M. Sioli,23b,23a G. Siragusa,176 I. Siral,104 S. Yu. Sivoklokov,112 J. Sjölin,44a,44b P. Skubic,127 M. Slater,21 T. Slavicek,141 M. Slawinska,83 K. Sliwa,169 R. Slovak,142 V. Smakhtin,179 B. H. Smart,5 J. Smiesko,28a N. Smirnov,111 S. Yu. Smirnov,111 Y. Smirnov,111 L. N. Smirnova,112,oo O. Smirnova,95 J. W. Smith,52 M. Smizanska,88 K. Smolek,141 A. Smykiewicz,83 A. A. Snesarev,109 I. M. Snyder,130 S. Snyder,29 R. Sobie,175,m A. M. Soffa,170 A. Soffer,160 A. Søgaard,49 D. A. Soh,157 G. Sokhrannyi,90 C. A. Solans Sanchez,36 M. Solar,141 E. Yu. Soldatov,111 U. Soldevila,173 A. A. Solodkov,122 A. Soloshenko,78 O. V. Solovyanov,122 V. Solovyev,137 P. Sommer,148 H. Son,169 W. Song,143 W. Y. Song,167b A. Sopczak,141 F. Sopkova,28b C. L. Sotiropoulou,70a,70b S. Sottocornola,69a,69b R. Soualah,65a,65c,pp A. M. Soukharev,121b,121a D. South,45 B. C. Sowden,92 S. Spagnolo,66a,66b M. Spalla,114 M. Spangenberg,177 F. Spanò,92 D. Sperlich,19 T. M. Spieker,60a R. Spighi,23b G. Spigo,36 L. A. Spiller,103 D. P. Spiteri,56 M. Spousta,142 A. Stabile,67a,67b R. Stamen,60a S. Stamm,19 E. Stanecka,83 R. W. Stanek,6 C. Stanescu,73a B. Stanislaus,134 M. M. Stanitzki,45 B. Stapf,119 S. Stapnes,133 E. A. Starchenko,122 G. H. Stark,37 J. Stark,57 S. H Stark,40 P. Staroba,140 P. Starovoitov,60a S. Stärz,36 R. Staszewski,83 M. Stegler,45 P. Steinberg,29 B. Stelzer,151 H. J. Stelzer,36 O. Stelzer-Chilton,167a H. Stenzel,55 T. J. Stevenson,155 G. A. Stewart,36 M. C. Stockton,36 G. Stoicea,27b P. Stolte,52 S. Stonjek,114 A. Straessner,47 J. Strandberg,153 S. Strandberg,44a,44b M. Strauss,127 P. Strizenec,28b R. Ströhmer,176 D. M. Strom,130 R. Stroynowski,42 A. Strubig,49 S. A. Stucci,29 B. Stugu,17 J. Stupak,127 N. A. Styles,45 D. Su,152 J. Su,138 S. Suchek,60a Y. Sugaya,132 M. Suk,141 V. V. Sulin,109 M. J. Sullivan,89 D. M. S. Sultan,53 S. Sultansoy,4c T. Sumida,84 S. Sun,104 X. Sun,3 K. Suruliz,155 C. J. E. Suster,156 M. R. Sutton,155 S. Suzuki,80 M. Svatos,140 M. Swiatlowski,37 S. P. Swift,2 A. Sydorenko,98 I. Sykora,28a T. Sykora,142 D. Ta,98 K. Tackmann,45 J. Taenzer,160 A. Taffard,170 R. Tafirout,167a E. Tahirovic,91 N. Taiblum,160 H. Takai,29 R. Takashima,85 E. H. Takasugi,114 K. Takeda,81 T. Takeshita,149 Y. Takubo,80 M. Talby,100 A. A. Talyshev,121b,121a J. Tanaka,162 M. Tanaka,164 R. Tanaka,131 B. B. Tannenwald,125 S. Tapia Araya,146b S. Tapprogge,98 A. Tarek Abouelfadl Mohamed,135 S. Tarem,159 G. Tarna,27b,p G. F. Tartarelli,67a P. Tas,142 M. Tasevsky,140 T. Tashiro,84 E. Tassi,41b,41a A. Tavares Delgado,139a,139b Y. Tayalati,35e A. C. Taylor,117 A. J. Taylor,49 G. N. Taylor,103 P. T. E. Taylor,103 W. Taylor,167b A. S. Tee,88 P. Teixeira-Dias,92 H. Ten Kate,36 J. J. Teoh,119 S. Terada,80 K. Terashi,162 J. Terron,97 S. Terzo,14 M. Testa,50 R. J. Teuscher,166,m S. J. Thais,182 T. Theveneaux-Pelzer,45 F. Thiele,40 D. W. Thomas,92 J. P. Thomas,21 A. S. Thompson,56 P. D. Thompson,21 L. A. Thomsen,182 E. Thomson,136 Y. Tian,39 R. E. Ticse Torres,52 V. O. Tikhomirov,109,qq Yu. A. Tikhonov,121b,121a S. Timoshenko,111 P. Tipton,182 S. Tisserant,100 K. Todome,164 S. Todorova-Nova,5 S. Todt,47 J. Tojo,86 S. Tokár,28a K. Tokushuku,80 E. Tolley,125 K. G. Tomiwa,33c M. Tomoto,116 L. Tompkins,152 K. Toms,117 B. Tong,58 P. Tornambe,51 E. Torrence,130 H. Torres,47 E. Torró Pastor,147 C. Tosciri,134 J. Toth,100,rr F. Touchard,100 D. R. Tovey,148 C. J. Treado,123 T. Trefzger,176 F. Tresoldi,155 A. Tricoli,29 I. M. Trigger,167a S. Trincaz-Duvoid,135 M. F. Tripiana,14 W. Trischuk,166 B. Trocmé,57 A. Trofymov,131 C. Troncon,67a M. Trovatelli,175 F. Trovato,155 L. Truong,33b M. Trzebinski,83 A. Trzupek,83 F. Tsai,45 J. C-L. Tseng,134 P. V. Tsiareshka,106 A. Tsirigotis,161 N. Tsirintanis,9 V. Tsiskaridze,154 E. G. Tskhadadze,158a I. I. Tsukerman,110 V. Tsulaia,18 S. Tsuno,80 D. Tsybychev,154 Y. Tu,62b A. Tudorache,27b V. Tudorache,27b T. T. Tulbure,27a A. N. Tuna,58 S. Turchikhin,78 D. Turgeman,179 I. Turk Cakir,4b,ss R. T. Turra,67a P. M. Tuts,39 E. Tzovara,98 G. Ucchielli,23b,23a I. Ueda,80 M. Ughetto,44a,44b F. Ukegawa,168 161801-15 PHYSICAL REVIEW LETTERS 123, 161801 (2019) G. Unal,36 A. Undrus,29 G. Unel,170 F. C. Ungaro,103 Y. Unno,80 K. Uno,162 J. Urban,28b P. Urquijo,103 P. Urrejola,98 G. Usai,8 J. Usui,80 L. Vacavant,100 V. Vacek,141 B. Vachon,102 K. O. H. Vadla,133 A. Vaidya,93 C. Valderanis,113 E. Valdes Santurio,44a,44b M. Valente,53 S. Valentinetti,23b,23a A. Valero,173 L. Valéry,45 R. A. Vallance,21 A. Vallier,5 J. A. Valls Ferrer,173 T. R. Van Daalen,14 H. Van der Graaf,119 P. Van Gemmeren,6 J. Van Nieuwkoop,151 I. Van Vulpen,119 M. Vanadia,72a,72b W. Vandelli,36 A. Vaniachine,165 P. Vankov,119 R. Vari,71a E. W. Varnes,7 C. Varni,54b,54a T. Varol,42 D. Varouchas,131 K. E. Varvell,156 G. A. Vasquez,146b J. G. Vasquez,182 F. Vazeille,38 D. Vazquez Furelos,14 T. Vazquez Schroeder,36 J. Veatch,52 V. Vecchio,73a,73b L. M. Veloce,166 F. Veloso,139a,139c S. Veneziano,71a A. Ventura,66a,66b M. Venturi,175 N. Venturi,36 V. Vercesi,69a M. Verducci,73a,73b C. M. Vergel Infante,77 C. Vergis,24 W. Verkerke,119 A. T. Vermeulen,119 J. C. Vermeulen,119 M. C. Vetterli,151,d N. Viaux Maira,146b M. Vicente Barreto Pinto,53 I. Vichou,172,a T. Vickey,148 O. E. Vickey Boeriu,148 G. H. A. Viehhauser,134 S. Viel,18 L. Vigani,134 M. Villa,23b,23a M. Villaplana Perez,67a,67b E. Vilucchi,50 M. G. Vincter,34 V. B. Vinogradov,78 A. Vishwakarma,45 C. Vittori,23b,23a I. Vivarelli,155 S. Vlachos,10 M. Vogel,181 P. Vokac,141 G. Volpi,14 S. E. von Buddenbrock,33c E. Von Toerne,24 V. Vorobel,142 K. Vorobev,111 M. Vos,173 J. H. Vossebeld,89 N. Vranjes,16 M. Vranjes Milosavljevic,16 V. Vrba,141 M. Vreeswijk,119 T. Šfiligoj,90 R. Vuillermet,36 I. Vukotic,37 T. Ženiš,28a L. Živković,16 P. Wagner,24 W. Wagner,181 J. Wagner-Kuhr,113 H. Wahlberg,87 S. Wahrmund,47 K. Wakamiya,81 V. M. Walbrecht,114 J. Walder,88 R. Walker,113 S. D. Walker,92 W. Walkowiak,150 V. Wallangen,44a,44b A. M. Wang,58 C. Wang,59b,p F. Wang,180 H. Wang,18 H. Wang,3 J. Wang,156 J. Wang,60b P. Wang,42 Q. Wang,127 R.-J. Wang,135 R. Wang,59a R. Wang,6 S. M. Wang,157 W. T. Wang,59a W. Wang,15c,tt W. X. Wang,59a,tt Y. Wang,59a,ff Z. Wang,59c C. Wanotayaroj,45 A. Warburton,102 C. P. Ward,32 D. R. Wardrope,93 A. Washbrook,49 P. M. Watkins,21 A. T. Watson,21 M. F. Watson,21 G. Watts,147 S. Watts,99 B. M. Waugh,93 A. F. Webb,11 S. Webb,98 C. Weber,182 M. S. Weber,20 S. A. Weber,34 S. M. Weber,60a A. R. Weidberg,134 B. Weinert,64 J. Weingarten,46 M. Weirich,98 C. Weiser,51 P. S. Wells,36 T. Wenaus,29 T. Wengler,36 S. Wenig,36 N. Wermes,24 M. D. Werner,77 P. Werner,36 M. Wessels,60a T. D. Weston,20 K. Whalen,130 N. L. Whallon,147 A. M. Wharton,88 A. S. White,104 A. White,8 M. J. White,1 R. White,146b D. Whiteson,170 B. W. Whitmore,88 F. J. Wickens,143 W. Wiedenmann,180 M. Wielers,143 C. Wiglesworth,40 L. A. M. Wiik-Fuchs,51 F. Wilk,99 H. G. Wilkens,36 L. J. Wilkins,92 H. H. Williams,136 S. Williams,32 C. Willis,105 S. Willocq,101 J. A. Wilson,21 I. Wingerter-Seez,5 E. Winkels,155 F. Winklmeier,130 O. J. Winston,155 B. T. Winter,51 M. Wittgen,152 M. Wobisch,94 A. Wolf,98 T. M. H. Wolf,119 R. Wolff,100 M. W. Wolter,83 H. Wolters,139a,139c V. W. S. Wong,174 N. L. Woods,145 S. D. Worm,21 B. K. Wosiek,83 K. W. Woźniak,83 K. Wraight,56 M. Wu,37 S. L. Wu,180 X. Wu,53 Y. Wu,59a T. R. Wyatt,99 B. M. Wynne,49 S. Xella,40 Z. Xi,104 L. Xia,177 D. Xu,15a H. Xu,59a,p L. Xu,29 T. Xu,144 W. Xu,104 B. Yabsley,156 S. Yacoob,33a K. Yajima,132 D. P. Yallup,93 D. Yamaguchi,164 Y. Yamaguchi,164 A. Yamamoto,80 T. Yamanaka,162 F. Yamane,81 M. Yamatani,162 T. Yamazaki,162 Y. Yamazaki,81 Z. Yan,25 H. J. Yang,59c,59d H. T. Yang,18 S. Yang,76 Y. Yang,162 Z. Yang,17 W-M. Yao,18 Y. C. Yap,45 Y. Yasu,80 E. Yatsenko,59c,59d J. Ye,42 S. Ye,29 I. Yeletskikh,78 E. Yigitbasi,25 E. Yildirim,98 K. Yorita,178 K. Yoshihara,136 C. J. S. Young,36 C. Young,152 J. Yu,77 J. Yu,8 X. Yue,60a S. P. Y. Yuen,24 B. Zabinski,83 G. Zacharis,10 E. Zaffaroni,53 R. Zaidan,14 A. M. Zaitsev,122,jj T. Zakareishvili,158b N. Zakharchuk,34 J. Zalieckas,17 S. Zambito,58 D. Zanzi,36 D. R. Zaripovas,56 S. V. Zeißner,46 C. Zeitnitz,181 G. Zemaityte,134 J. C. Zeng,172 Q. Zeng,152 O. Zenin,122 D. Zerwas,131 M. Zgubič,134 D. F. Zhang,59b D. Zhang,104 F. Zhang,180 G. Zhang,59a G. Zhang,15b H. Zhang,15c J. Zhang,6 L. Zhang,15c L. Zhang,59a M. Zhang,172 P. Zhang,15c R. Zhang,59a R. Zhang,24 X. Zhang,59b Y. Zhang,15a,15d Z. Zhang,131 P. Zhao,48 Y. Zhao,59b,131,x Z. Zhao,59a A. Zhemchugov,78 Z. Zheng,104 D. Zhong,172 B. Zhou,104 C. Zhou,180 L. Zhou,42 M. S. Zhou,15a,15d M. Zhou,154 N. Zhou,59c Y. Zhou,7 C. G. Zhu,59b H. L. Zhu,59a H. Zhu,15a J. Zhu,104 Y. Zhu,59a X. Zhuang,15a K. Zhukov,109 V. Zhulanov,121b,121a A. Zibell,176 D. Zieminska,64 N. I. Zimine,78 S. Zimmermann,51 Z. Zinonos,114 M. Zinser,98 M. Ziolkowski,150 G. Zobernig,180 A. Zoccoli,23b,23a K. Zoch,52 T. G. Zorbas,148 R. Zou,37 M. Zur Nedden,19 and L. Zwalinski36 (ATLAS Collaboration) 1 Department of Physics, University of Adelaide, Adelaide, Australia 2 Physics Department, SUNY Albany, Albany, New York, USA 3 Department of Physics, University of Alberta, Edmonton, Alberta, Canada 4a Department of Physics, Ankara University, Ankara, Turkey 4b Istanbul Aydin University, Istanbul, Turkey 161801-16 PHYSICAL REVIEW LETTERS 123, 161801 (2019) 4c Division of Physics, TOBB University of Economics and Technology, Ankara, Turkey 5 LAPP, Université Grenoble Alpes, Université Savoie Mont Blanc, CNRS/IN2P3, Annecy, France 6 High Energy Physics Division, Argonne National Laboratory, Argonne, Illinois, USA 7 Department of Physics, University of Arizona, Tucson, Arizona, USA 8 Department of Physics, University of Texas at Arlington, Arlington, Texas, USA 9 Physics Department, National and Kapodistrian University of Athens, Athens, Greece 10 Physics Department, National Technical University of Athens, Zografou, Greece 11 Department of Physics, University of Texas at Austin, Austin, Texas, USA 12a Bahcesehir University, Faculty of Engineering and Natural Sciences, Istanbul, Turkey 12b Istanbul Bilgi University, Faculty of Engineering and Natural Sciences, Istanbul, Turkey 12c Department of Physics, Bogazici University, Istanbul, Turkey 12d Department of Physics Engineering, Gaziantep University, Gaziantep, Turkey 13 Institute of Physics, Azerbaijan Academy of Sciences, Baku, Azerbaijan 14 Institut de Física d’Altes Energies (IFAE), Barcelona Institute of Science and Technology, Barcelona, Spain 15a Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China 15b Physics Department, Tsinghua University, Beijing, China 15c Department of Physics, Nanjing University, Nanjing, China 15d University of Chinese Academy of Science (UCAS), Beijing, China 16 Institute of Physics, University of Belgrade, Belgrade, Serbia 17 Department for Physics and Technology, University of Bergen, Bergen, Norway 18 Physics Division, Lawrence Berkeley National Laboratory and University of California, Berkeley, California, USA 19 Institut für Physik, Humboldt Universität zu Berlin, Berlin, Germany 20 Albert Einstein Center for Fundamental Physics and Laboratory for High Energy Physics, University of Bern, Bern, Switzerland 21 School of Physics and Astronomy, University of Birmingham, Birmingham, United Kingdom 22 Facultad de Ciencias y Centro de Investigaciónes, Universidad Antonio Nariño, Bogota, Colombia 23a INFN Bologna and Universita’ di Bologna, Dipartimento di Fisica, Italy 23b INFN Sezione di Bologna, Italy 24 Physikalisches Institut, Universität Bonn, Bonn, Germany 25 Department of Physics, Boston University, Boston, Massachusetts, USA 26 Department of Physics, Brandeis University, Waltham, Massachusetts, USA 27a Transilvania University of Brasov, Brasov, Romania 27b Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest, Romania 27c Department of Physics, Alexandru Ioan Cuza University of Iasi, Iasi, Romania 27d National Institute for Research and Development of Isotopic and Molecular Technologies, Physics Department, Cluj-Napoca, Romania 27e University Politehnica Bucharest, Bucharest, Romania 27f West University in Timisoara, Timisoara, Romania 28a Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, Slovak Republic 28b Department of Subnuclear Physics, Institute of Experimental Physics of the Slovak Academy of Sciences, Kosice, Slovak Republic 29 Physics Department, Brookhaven National Laboratory, Upton, New York, USA 30 Departamento de Física, Universidad de Buenos Aires, Buenos Aires, Argentina 31 California State University, California, USA 32 Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom 33a Department of Physics, University of Cape Town, Cape Town, South Africa 33b Department of Mechanical Engineering Science, University of Johannesburg, Johannesburg, South Africa 33c School of Physics, University of the Witwatersrand, Johannesburg, South Africa 34 Department of Physics, Carleton University, Ottawa, Ontario, Canada 35a Faculté des Sciences Ain Chock, Réseau Universitaire de Physique des Hautes Energies-Université Hassan II, Casablanca, Morocco 35b Faculté des Sciences, Université Ibn-Tofail, Kénitra, Morocco 35c Faculté des Sciences Semlalia, Université Cadi Ayyad, LPHEA-Marrakech, Morocco 35d Faculté des Sciences, Université Mohamed Premier and LPTPM, Oujda, Morocco 35e Faculté des sciences, Université Mohammed V, Rabat, Morocco 36 CERN, Geneva, Switzerland 37 Enrico Fermi Institute, University of Chicago, Chicago, Illinois, USA 38 LPC, Université Clermont Auvergne, CNRS/IN2P3, Clermont-Ferrand, France 39 Nevis Laboratory, Columbia University, Irvington, New York, USA 40 Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark 41a Dipartimento di Fisica, Università della Calabria, Rende, Italy 41b INFN Gruppo Collegato di Cosenza, Laboratori Nazionali di Frascati, Italy 42 Physics Department, Southern Methodist University, Dallas, Texas, USA 161801-17 PHYSICAL REVIEW LETTERS 123, 161801 (2019) 43 Physics Department, University of Texas at Dallas, Richardson, Texas, USA 44a Department of Physics, Stockholm University, Sweden 44b Oskar Klein Centre, Stockholm, Sweden 45 Deutsches Elektronen-Synchrotron DESY, Hamburg and Zeuthen, Germany 46 Lehrstuhl für Experimentelle Physik IV, Technische Universität Dortmund, Dortmund, Germany 47 Institut für Kern- und Teilchenphysik, Technische Universität Dresden, Dresden, Germany 48 Department of Physics, Duke University, Durham, North Carolina, USA 49 SUPA-School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom 50 INFN e Laboratori Nazionali di Frascati, Frascati, Italy 51 Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany 52 II. Physikalisches Institut, Georg-August-Universität Göttingen, Göttingen, Germany 53 Département de Physique Nucléaire et Corpusculaire, Université de Genève, Genève, Switzerland 54a Dipartimento di Fisica, Università di Genova, Genova, Italy 54b INFN Sezione di Genova, Italy 55 II. Physikalisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany 56 SUPA-School of Physics and Astronomy, University of Glasgow, Glasgow, United Kingdom 57 LPSC, Université Grenoble Alpes, CNRS/IN2P3, Grenoble INP, Grenoble, France 58 Laboratory for Particle Physics and Cosmology, Harvard University, Cambridge, Massachusetts, USA 59a Department of Modern Physics and State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei, China 59b Institute of Frontier and Interdisciplinary Science and Key Laboratory of Particle Physics and Particle Irradiation (MOE), Shandong University, Qingdao, China 59c School of Physics and Astronomy, Shanghai Jiao Tong University, KLPPAC-MoE, SKLPPC, Shanghai, China 59d Tsung-Dao Lee Institute, Shanghai, China 60a Kirchhoff-Institut für Physik, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany 60b Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany 61 Faculty of Applied Information Science, Hiroshima Institute of Technology, Hiroshima, Japan 62a Department of Physics, Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China 62b Department of Physics, University of Hong Kong, Hong Kong, China 62c Department of Physics and Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China 63 Department of Physics, National Tsing Hua University, Hsinchu, Taiwan 64 Department of Physics, Indiana University, Bloomington, Indiana, USA 65a INFN Gruppo Collegato di Udine, Sezione di Trieste, Udine, Italy 65b ICTP, Trieste, Italy 65c Dipartimento Politecnico di Ingegneria e Architettura, Università di Udine, Udine, Italy 66a INFN Sezione di Lecce, Italy 66b Dipartimento di Matematica e Fisica, Università del Salento, Lecce, Italy 67a INFN Sezione di Milano, Italy 67b Dipartimento di Fisica, Università di Milano, Milano, Italy 68a INFN Sezione di Napoli, Italy 68b Dipartimento di Fisica, Università di Napoli, Napoli, Italy 69a INFN Sezione di Pavia, Italy 69b Dipartimento di Fisica, Università di Pavia, Pavia, Italy 70a INFN Sezione di Pisa, Italy 70b Dipartimento di Fisica E. Fermi, Università di Pisa, Pisa, Italy 71a INFN Sezione di Roma, Italy 71b Dipartimento di Fisica, Sapienza Università di Roma, Roma, Italy 72a INFN Sezione di Roma Tor Vergata, Italy 72b Dipartimento di Fisica, Università di Roma Tor Vergata, Roma, Italy 73a INFN Sezione di Roma Tre, Italy 73b Dipartimento di Matematica e Fisica, Università Roma Tre, Roma, Italy 74a INFN-TIFPA, Italy 74b Università degli Studi di Trento, Trento, Italy 75 Institut für Astro- und Teilchenphysik, Leopold-Franzens-Universität, Innsbruck, Austria 76 University of Iowa, Iowa City, Iowa, USA 77 Department of Physics and Astronomy, Iowa State University, Ames, Iowa, USA 78 Joint Institute for Nuclear Research, Dubna, Russia 79a Departamento de Engenharia Elétrica, Universidade Federal de Juiz de Fora (UFJF), Juiz de Fora, Brazil 79b Universidade Federal do Rio De Janeiro COPPE/EE/IF, Rio de Janeiro, Brazil 161801-18 PHYSICAL REVIEW LETTERS 123, 161801 (2019) 79c Universidade Federal de São João del Rei (UFSJ), São João del Rei, Brazil 79d Instituto de Física, Universidade de São Paulo, São Paulo, Brazil 80 KEK, High Energy Accelerator Research Organization, Tsukuba, Japan 81 Graduate School of Science, Kobe University, Kobe, Japan 82a AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Krakow, Poland 82b Marian Smoluchowski Institute of Physics, Jagiellonian University, Krakow, Poland 83 Institute of Nuclear Physics Polish Academy of Sciences, Krakow, Poland 84 Faculty of Science, Kyoto University, Kyoto, Japan 85 Kyoto University of Education, Kyoto, Japan 86 Research Center for Advanced Particle Physics and Department of Physics, Kyushu University, Fukuoka, Japan 87 Instituto de Física La Plata, Universidad Nacional de La Plata and CONICET, La Plata, Argentina 88 Physics Department, Lancaster University, Lancaster, United Kingdom 89 Oliver Lodge Laboratory, University of Liverpool, Liverpool, United Kingdom 90 Department of Experimental Particle Physics, Jožef Stefan Institute and Department of Physics, University of Ljubljana, Ljubljana, Slovenia 91 School of Physics and Astronomy, Queen Mary University of London, London, United Kingdom 92 Department of Physics, Royal Holloway University of London, Egham, United Kingdom 93 Department of Physics and Astronomy, University College London, London, United Kingdom 94 Louisiana Tech University, Ruston, Louisiana, USA 95 Fysiska institutionen, Lunds universitet, Lund, Sweden 96 Centre de Calcul de l’Institut National de Physique Nucléaire et de Physique des Particules (IN2P3), Villeurbanne, France 97 Departamento de Física Teorica C-15 and CIAFF, Universidad Autónoma de Madrid, Madrid, Spain 98 Institut für Physik, Universität Mainz, Mainz, Germany 99 School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom 100 CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille, France 101 Department of Physics, University of Massachusetts, Amherst, Massachusetts, USA 102 Department of Physics, McGill University, Montreal, Quebec, Canada 103 School of Physics, University of Melbourne, Victoria, Australia 104 Department of Physics, University of Michigan, Ann Arbor, Michigan, USA 105 Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan, USA 106 B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, Minsk, Belarus 107 Research Institute for Nuclear Problems of Byelorussian State University, Minsk, Belarus 108 Group of Particle Physics, University of Montreal, Montreal, Quebec, Canada 109 P.N. Lebedev Physical Institute of the Russian Academy of Sciences, Moscow, Russia 110 Institute for Theoretical and Experimental Physics of the National Research Centre Kurchatov Institute, Moscow, Russia 111 National Research Nuclear University MEPhI, Moscow, Russia 112 D.V. Skobeltsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, Moscow, Russia 113 Fakultät für Physik, Ludwig-Maximilians-Universität München, München, Germany 114 Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), München, Germany 115 Nagasaki Institute of Applied Science, Nagasaki, Japan 116 Graduate School of Science and Kobayashi-Maskawa Institute, Nagoya University, Nagoya, Japan 117 Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico, USA 118 Institute for Mathematics, Astrophysics and Particle Physics, Radboud University Nijmegen/Nikhef, Nijmegen, Netherlands 119 Nikhef National Institute for Subatomic Physics and University of Amsterdam, Amsterdam, Netherlands 120 Department of Physics, Northern Illinois University, DeKalb, Illinois, USA 121a Budker Institute of Nuclear Physics and NSU, SB RAS, Novosibirsk, Russia 121b Novosibirsk State University Novosibirsk, Russia 122 Institute for High Energy Physics of the National Research Centre Kurchatov Institute, Protvino, Russia 123 Department of Physics, New York University, New York, New York, USA 124 Ochanomizu University, Otsuka, Bunkyo-ku, Tokyo, Japan 125 Ohio State University, Columbus, Ohio, USA 126 Faculty of Science, Okayama University, Okayama, Japan 127 Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, Oklahoma, USA 128 Department of Physics, Oklahoma State University, Stillwater, Oklahoma, USA 129 Palacký University, RCPTM, Joint Laboratory of Optics, Olomouc, Czech Republic 130 Center for High Energy Physics, University of Oregon, Eugene, Oregon, USA 131 LAL, Université Paris-Sud, CNRS/IN2P3, Université Paris-Saclay, Orsay, France 132 Graduate School of Science, Osaka University, Osaka, Japan 133 Department of Physics, University of Oslo, Oslo, Norway 134 Department of Physics, Oxford University, Oxford, United Kingdom 161801-19 PHYSICAL REVIEW LETTERS 123, 161801 (2019) 135 LPNHE, Sorbonne Université, Paris Diderot Sorbonne Paris Cité, CNRS/IN2P3, Paris, France 136 Department of Physics, University of Pennsylvania, Philadelphia, Pennsylvania, USA 137 Konstantinov Nuclear Physics Institute of National Research Centre “Kurchatov Institute”, PNPI, St. Petersburg, Russia 138 Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania, USA 139a Laboratório de Instrumentação e Física Experimental de Partículas-LIP, Portugal 139b Departamento de Física, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal 139c Departamento de Física, Universidade de Coimbra, Coimbra, Portugal 139d Centro de Física Nuclear da Universidade de Lisboa, Lisboa, Portugal 139e Departamento de Física, Universidade do Minho, Braga, Portugal 139f Universidad de Granada, Granada (Spain), Spain 139g Dep Física and CEFITEC of Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal 140 Institute of Physics of the Czech Academy of Sciences, Prague, Czech Republic 141 Czech Technical University in Prague, Prague, Czech Republic 142 Charles University, Faculty of Mathematics and Physics, Prague, Czech Republic 143 Particle Physics Department, Rutherford Appleton Laboratory, Didcot, United Kingdom 144 IRFU, CEA, Université Paris-Saclay, Gif-sur-Yvette, France 145 Santa Cruz Institute for Particle Physics, University of California Santa Cruz, Santa Cruz, California, USA 146a Departamento de Física, Pontificia Universidad Católica de Chile, Santiago, Chile 146b Departamento de Física, Universidad Técnica Federico Santa María, Valparaíso, Chile 147 Department of Physics, University of Washington, Seattle, Washington, USA 148 Department of Physics and Astronomy, University of Sheffield, Sheffield, United Kingdom 149 Department of Physics, Shinshu University, Nagano, Japan 150 Department Physik, Universität Siegen, Siegen, Germany 151 Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada 152 SLAC National Accelerator Laboratory, Stanford, California, USA 153 Physics Department, Royal Institute of Technology, Stockholm, Sweden 154 Departments of Physics and Astronomy, Stony Brook University, Stony Brook, New York, USA 155 Department of Physics and Astronomy, University of Sussex, Brighton, United Kingdom 156 School of Physics, University of Sydney, Sydney, Australia 157 Institute of Physics, Academia Sinica, Taipei, Taiwan 158a E. Andronikashvili Institute of Physics, Iv. Javakhishvili Tbilisi State University, Tbilisi, Georgia 158b High Energy Physics Institute, Tbilisi State University, Tbilisi, Georgia 159 Department of Physics, Technion, Israel Institute of Technology, Haifa, Israel 160 Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv, Israel 161 Department of Physics, Aristotle University of Thessaloniki, Thessaloniki, Greece 162 International Center for Elementary Particle Physics and Department of Physics, University of Tokyo, Tokyo, Japan 163 Graduate School of Science and Technology, Tokyo Metropolitan University, Tokyo, Japan 164 Department of Physics, Tokyo Institute of Technology, Tokyo, Japan 165 Tomsk State University, Tomsk, Russia 166 Department of Physics, University of Toronto, Toronto, Ontario, Canada 167a TRIUMF, Vancouver, British Columbia, Canada 167b Department of Physics and Astronomy, York University, Toronto, Ontario, Canada 168 Division of Physics and Tomonaga Center for the History of the Universe, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Japan 169 Department of Physics and Astronomy, Tufts University, Medford, Massachusetts, USA 170 Department of Physics and Astronomy, University of California Irvine, Irvine, California, USA 171 Department of Physics and Astronomy, University of Uppsala, Uppsala, Sweden 172 Department of Physics, University of Illinois, Urbana, Illinois, USA 173 Instituto de Física Corpuscular (IFIC), Centro Mixto Universidad de Valencia-CSIC, Valencia, Spain 174 Department of Physics, University of British Columbia, Vancouver, British Columbia, Canada 175 Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, Canada 176 Fakultät für Physik und Astronomie, Julius-Maximilians-Universität Würzburg, Würzburg, Germany 177 Department of Physics, University of Warwick, Coventry, United Kingdom 178 Waseda University, Tokyo, Japan 179 Department of Particle Physics, Weizmann Institute of Science, Rehovot, Israel 180 Department of Physics, University of Wisconsin, Madison, Wisconsin, USA 181 Fakultät für Mathematik und Naturwissenschaften, Fachgruppe Physik, Bergische Universität Wuppertal, Wuppertal, Germany 182 Department of Physics, Yale University, New Haven, Connecticut, USA 183 Yerevan Physics Institute, Yerevan, Armenia 161801-20 PHYSICAL REVIEW LETTERS 123, 161801 (2019) a Deceased. b Also at Department of Physics, King’s College London, London, United Kingdom. c Also at Institute of Physics, Azerbaijan Academy of Sciences, Baku, Azerbaijan. d Also at TRIUMF, Vancouver, British Columbia, Canada. e Also at Department of Physics and Astronomy, University of Louisville, Louisville, Kentucky, USA. f Also at Physics Department, An-Najah National University, Nablus, Palestine. g Also at Department of Physics, California State University, Fresno, USA. h Also at Department of Physics, University of Fribourg, Fribourg, Switzerland. i Also at Departament de Fisica de la Universitat Autonoma de Barcelona, Barcelona, Spain. j Also at Tomsk State University, Tomsk, and Moscow Institute of Physics and Technology State University, Dolgoprudny, Russia. k Also at The Collaborative Innovation Center of Quantum Matter (CICQM), Beijing, China. l Also at Universita di Napoli Parthenope, Napoli, Italy. m Also at Institute of Particle Physics (IPP), Canada. n Also at II. Physikalisches Institut, Georg-August-Universität Göttingen, Göttingen, Germany. o Also at Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest, Romania. p Also at CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille, France. q Also at Department of Physics, St. Petersburg State Polytechnical University, St. Petersburg, Russia. r Also at Borough of Manhattan Community College, City University of New York, New York, New York, USA. s Also at Department of Financial and Management Engineering, University of the Aegean, Chios, Greece. t Also at Centre for High Performance Computing, CSIR Campus, Rosebank, Cape Town, South Africa. u Also at Department of Physics, California State University, East Bay, USA. v Also at Institucio Catalana de Recerca i Estudis Avancats, ICREA, Barcelona, Spain. w Also at Department of Physics, University of Michigan, Ann Arbor, Michigan, USA. x Also at LAL, Université Paris-Sud, CNRS/IN2P3, Université Paris-Saclay, Orsay, France. y Also at Graduate School of Science, Osaka University, Osaka, Japan. z Also at Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany. aa Also at Institute for Mathematics, Astrophysics and Particle Physics, Radboud University Nijmegen/Nikhef, Nijmegen, Netherlands. bb Also at Institute of Theoretical Physics, Ilia State University, Tbilisi, Georgia. cc Also at CERN, Geneva, Switzerland. dd Also at Manhattan College, New York, New York, USA. ee Also at Hellenic Open University, Patras, Greece. ff Also at LPNHE, Sorbonne Université, Paris Diderot Sorbonne Paris Cité, CNRS/IN2P3, Paris, France. gg Also at The City College of New York, New York, New York, USA. hh Also at Universidad de Granada, Granada (Spain), Spain. ii Also at Department of Physics, California State University, Sacramento, USA. jj Also at Moscow Institute of Physics and Technology State University, Dolgoprudny, Russia. kk Also at Département de Physique Nucléaire et Corpusculaire, Université de Genève, Genève, Switzerland. ll Also at Department of Physics and Astronomy, University of Sheffield, Sheffield, United Kingdom. mm Also at Louisiana Tech University, Ruston, Louisiana, USA. nn Also at School of Physics, Sun Yat-sen University, Guangzhou, China. oo Also at Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow, Russia. pp Also at Department of Applied Physics and Astronomy, University of Sharjah, Sharjah, United Arab Emirates. qq Also at National Research Nuclear University MEPhI, Moscow, Russia. rr Also at Institute for Particle and Nuclear Physics, Wigner Research Centre for Physics, Budapest, Hungary. ss Also at Giresun University, Faculty of Engineering, Giresun, Turkey. tt Also at Institute of Physics, Academia Sinica, Taipei, Taiwan. 161801-21