Predicting positive parity $B_{s}$ mesons from lattice QCD

TL;DR

This study uses lattice QCD to predict the spectrum of $B_s$ mesons, confirming known states and predicting new bound states near thresholds, with results aligning well with experimental data and theoretical expectations.

Contribution

First-principles lattice QCD calculations of $B_s$ meson spectrum, including predictions of new bound states near thresholds, advancing understanding of heavy meson spectroscopy.

Findings

Good agreement with experimental $B_{s1}(5830)$ and $B_{s2}^*(5840)$ masses.

Prediction of a $J^P=0^+$ bound state $B_{s0}$ at 5.711 GeV.

Prediction of a $J^P=1^+$ bound state $B_{s1}$ at 5.750 GeV.

Abstract

We determine the spectrum of $B_s$ 1P states using lattice QCD. For the $B_{s1}(5830)$ and $B_{s2}^*(5840)$ 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 $B^{*}K$ thresholds. A combination of quark-antiquark and $B^{(*)}$ meson-Kaon interpolating fields are used to determine the mass of two QCD bound states below the $B^{(*)}K$ threshold, with the assumption that mixing with $B_s^{(*)}\eta$ and isospin-violating decays to $B_s^{(*)}\pi$ 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.