Threshold effects in P-wave bottom-strange mesons

Abstract

Using a nonrelativistic constituent quark model in which the degrees of freedom are quark-antiquark and meson-meson components, we have recently shown that the D(*)K thresholds play an important role in lowering the mass of the cs¯ states associated with the physical Ds0*(2317) and Ds1(2460) mesons. This observation is also supported by other theoretical approaches such as lattice-regularized QCD or chiral unitary theory in coupled channels. Herein, we extend our computation to the lowest P-wave Bs mesons, taking into account the corresponding JP=0_s16, 1_s16 and 2_s16 bottom-strange states predicted by the naive quark model and the BK and B*K thresholds. We assume that mixing with Bs(*)η and isospin-violating decays to Bs(*)Ï_s08 are negligible. This computation is important because there is no experimental data in the bs¯ sector for the equivalent jqP=1/2_s16 (Ds0*(2317), Ds1(2460)) heavy-quark multiplet and, as it has been seen in the cs¯ sector, the naive theoretical result can be wrong by more than 100 MeV. Our calculation allows us to introduce the coupling with the D-wave B*K channel and to compute the probabilities associated with the different Fock components of the physical state.