Spectroscopy of Bc mesons and the possibility of finding exotic Bc-like structures

The bottom-charmed (B-c) mesons are more stable than their charmonium (c (c) over bar) and bottomium (b (b) over bar) 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 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 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(+) and J(P) = 1(+) sectors. However, in the J(P) = 2(+) sector we found an additional state very close to the D* B* threshold which could be experimentally detected.