The Zc structures in a coupled-channels model
Ortega, Pablo G. (Universidad de Salamanca. Instituto Universitario de Física Fundamental y Matemáticas)
Segovia, Jorge (Universitat Autònoma de Barcelona. Departament de Física)
Entem, David R. (Universidad de Salamanca. Instituto Universitario de Física Fundamental y Matemáticas)
Fernández, Francisco (Universidad de Salamanca. Instituto Universitario de Física Fundamental y Matemáticas)

Data:	2019
Resum:	The Z(3900) / Z(3885) and Z(4020) are two charmonium-like structures discovered in the πJ/ ψ and DD¯ + h. c. invariant mass spectra. Their nature is puzzling due to their charge, which forces its minimal quark content to be cc¯ ud¯ (cc¯ du¯). Thus, it is necessary to explore four-quark systems in order to understand their inner structure. Additionally, their strong coupling to channels such as πJ/ ψ and the closeness of their mass to DD¯ -thresholds stimulates both a molecular interpretation or a coupled-channels threshold effect. In this work we perform a coupled-channels calculation of the I(J) = 1 (1 ) sector including DD¯ + h. c. , πJ/ ψ and ρη channels in the framework of a constituent quark model which satisfactorily describes a wide range of properties of (non-)conventional hadrons containing heavy quarks. The meson-meson interactions are dominated by the non-diagonal πJ/ ψ- DD¯ and ρη- DD¯ couplings which indicates that the Z(3900) / Z(3885) and Z(4020) are unusual structures. The study of the analytic structure of the S-matrix allows us to conclude that the point-wise behavior of the line shapes in the πJ/ ψ and DD¯ invariant mass distributions is due to the presence of two virtual states that produce the Z peaks.
Ajuts:	Ministerio de Economía y Competitividad FPA-2016-77177-C2-2-P Ministerio de Economía y Competitividad FPA-2014-55613-P Ministerio de Economía y Competitividad FPA-2017-86989-P Ministerio de Economía y Competitividad IJCI-2016-28525.J.S European Commission 665919 Ministerio de Economía y Competitividad IJCI-2016-30028
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Publicat a:	The European Physical Journal. C, Particles and Fields, Vol. 79, Issue 1 (January 2019) , art. 78, ISSN 1434-6052

DOI: 10.1140/epjc/s10052-019-6552-7

10 p, 735.6 KB

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