Unraveling the pattern of the $XYZ$ mesons

Abstract

We present a plausible mechanism for the origin of the $XYZ$ mesons in the heavy meson spectra within a standard quark-model picture. We discuss the conditions required for the existence of four--quark bound states or resonances contributing to the heavy meson spectra, being either compact or molecular. We concentrate on charmonium and bottomonium spectra, where several new states, difficult to understand as simple quark-antiquark pairs, have been reported by different experimental collaborations. The pivotal role played by entangled meson-meson thresholds is emphasized.

8 pages, 2 figures

References in corpus (7)

• Constituent quark model study of the meson spectra
• Excited and exotic charmonium spectroscopy from lattice QCD
• Quark-model study of few-baryon systems
• Charmonium spectroscopy above thresholds
• Do $c\bar{c}n\bar{n}$ bound states exist?
• Study of the baryonic B decay B- -> SigmaC++ p- pi- pi-
• Multiquark contributions to charm baryon spectroscopy

Cited by in corpus (13)

• The hidden-charm pentaquark and tetraquark states
• Phenomenology of $P_c(4380{)}^{+}$, $P_c(4450{)}^{+}$ and related states
• Weak decays of heavy hadrons into dynamically generated resonances
• Charm-beauty meson bound states from $B(B^{\ast })D(D^{\ast })$ and $B(B^{\ast })\bar{D}({\bar{D}}^{\ast })$ interaction
• The $X(4140)$, $X(4274)$, $X(4500)$ and $X(4700)$ in the relativized quark model
• Exotic $bc\bar{q}\bar{q}$ four-quark states
• Heavy flavor dibaryons
• Width of a two-body coupled-channel resonance
• Understanding close-lying exotic charmonia states within QCD sum rules
• Hadronic resonances enhanced by thresholds
• Hidden and open heavy-flavor hadronic states
• Production of $X_{cs\bar{c}\bar{s}}$ in heavy ion collisions
• On the Origin of the $XYZ$ Mesons