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

• Main Authors: Pablo G. Ortega, Jorge Segovia, David R. Entem, Francisco Fernández
• Format: Article
• Language: English
• Published: SpringerOpen 2020-03-01
• Series: European Physical Journal C: Particles and Fields
• Online Access: http://link.springer.com/article/10.1140/epjc/s10052-020-7764-6

Abstract The 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.