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 $c\overline{s}$ states associated with the physical $D_{s0}^{*}(2317)$ and $D_{s1}(2460)$ 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 $B_s$ mesons, taking into account the corresponding $J^P=0^{+}$, $1^{+}$ and $2^{+}$ bottom-strange states predicted by the naive quark model and the $BK$ and $B^{*}K$ thresholds. We assume that mixing with $B_s^{(*)}\eta$ and isospin-violating decays to $B_s^{(*)}\pi$ are negligible. This computation is important because there is no experimental data in the $b\overline{s}$ sector for the equivalent $j_q^P=1/2^{+}$ ($D_{s0}^{*}(2317)$, $D_{s1}(2460)$) heavy-quark multiplet and, as it has been seen in the $c\overline{s}$ 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.

• Received 20 December 2016

DOI:https://doi.org/10.1103/PhysRevD.95.034010