Predicting positive parity $B_s$ mesons from lattice QCD

Abstract

We determine the spectrum of $B_s$ 1P states using lattice QCD. For the $B_{s1}(5830)$ and $B_{s2}^{\ast }(5840)$ mesons, the results are in good agreement with the experimental values. Two further mesons are expected in the quantum channels $J^P=0^{+}$ and $1^{+}$ near the $BK$ and $B^{\ast }K$ thresholds. A combination of quark-antiquark and $B^{(\ast )}$ meson-Kaon interpolating fields are used to determine the mass of two QCD bound states below the $B^{(\ast )}K$ threshold, with the assumption that mixing with $B_s^{(\ast )}\eta$ and isospin-violating decays to $B_s^{(\ast )}\pi$ are negligible. We predict a $J^P=0^{+}$ bound state $B_{s0}$ with mass $m_{B_{s0}}=5.711(13)(19)$ GeV. With further assumptions motivated theoretically by the heavy quark limit, a bound state with $m_{B_{s1}}=5.750(17)(19)$ GeV is predicted in the $J^P=1^{+}$ channel. The results from our first principles calculation are compared to previous model-based estimates.

Comments: 5 pages, 2 figures; Final version