Spectroscopy of $$\mathbf {B_c}$$ mesons and the possibility of finding exotic $$\mathbf {B_c}$$-like structures

Abstract

AbstractThe bottom-charmed ($$B_c$$Bc) mesons are more stable than their charmonium ($$c{{\bar{c}}}$$cc¯) and bottomium ($$b{{\bar{b}}}$$bb¯) partners because they cannot annihilate into gluons. However, the low production cross-sections and signal-to-background ratios avoided until now their clear identification. The recent experimental results reported by CMS and LHCb at CERN open the possibility of having a $$B_c$$Bc spectrum as complete as the ones of charmonium and bottomonium. Motivated by this expectation, we compute bottom-charmed meson masses in the region energies in which decay meson–meson thresholds are opened, looking for the analogs to the X(3872) in the $$B_c$$Bc spectroscopy. We use a constituent quark model in which quark–antiquark degrees of freedom are complemented by four-body Fock states configurations. The model has been applied to a wide range of hadronic observables, in particular to the X(3872), and thus the model parameters are completely constrained. No extra states are found in the $$J^P=0^+$$JP=0+ and $$J^P=1^+$$JP=1+ sectors. However, in the $$J^P=2^+$$JP=2+ sector we found an additional state very close to the $$D^*B^*$$D∗B∗ threshold which could be experimentally detected.