Charmonium resonances in the 3.9 GeV/$c^2$ energy region and the $X(3915)/X(3930)$ puzzle

Abstract

An interesting controversy has emerged challenging the widely accepted nature of the $X(3915)$ and the $X(3930)$ resonances, which had initially been assigned to the ${\chi }_{c0}(2P)$ and ${\chi }_{c2}(2P)$ $c\bar{c}$ states, respectively. To unveil their inner structure, the properties of the $J^{PC}=0^{++}$ and $J^{PC}=2^{++}$ charmonium states in the energy region of these resonances are analyzed in the framework of a constituent quark model. Together with the bare $q\bar{q}$ states, threshold effects due to the opening of nearby meson-meson channels are included in a coupled-channels scheme calculation. We find that the structure of both states is dominantly molecular with a probability of bare $q\bar{q}$ states lower than $45\%$. Our results favor the hypothesis that $X(3915)$ and $X(3930)$ resonances arise as different decay mechanisms of the same $J^{PC}=2^{++}$ state. Moreover we found an explanation for the recently discovered $M=3860$ MeV$/c^2$ as a $J^{PC}=0^{++}$ $2P$ state and rediscovery the lost $Y(3940)$ as an additional state in the $J^{PC}=0^{++}$ family.

6 pages, 3 tables

References in corpus (8)

• Constituent quark model study of the meson spectra
• Quark-model study of few-baryon systems
• Decay channels and charmonium mass-shifts
• Where is the χ_{c0}(2P)?
• Interplay of quark and meson degrees of freedom in a near-threshold resonance
• Could the $X(3915)$ and the $X(3930)$ Be the Same Tensor State?
• Is the X(3915) the chi_{c0}(2P)?
• Radiative decays of the Y(3940), Z(3930) and the X(4160) as dynamically generated resonances

Cited by in corpus (4)

• $QQ\bar{s}\bar{s}$ tetraquarks in the chiral quark model
• Diabatic description of charmoniumlike mesons II: mass corrections and strong decay widths
• Study of conventional and non-conventional scalar and vector mesons
• Coupled-channel meson-meson scattering in the diabatic framework