Bottom hadron mass splittings in the static limit from 2+1 flavour lattice QCD

TL;DR

This study uses 2+1 flavour lattice QCD with domain-wall fermions to compute bottom hadron mass splittings in the static limit, showing good agreement with experiments but slight underestimation for Omega_b^- baryon splittings.

Contribution

First lattice QCD calculation of bottom hadron mass splittings in the static limit using dynamical 2+1 flavour configurations with domain-wall fermions.

Findings

Results agree with experimental data in the bottom sector.

Static limit splittings slightly underestimate recent measurements for Omega_b^-.

Calculations are based on configurations with pion mass down to 275 MeV.

Abstract

Dynamical 2+1 flavour lattice QCD is used to calculate the splittings between the masses of mesons and baryons containing a single static heavy quark and domain-wall light and strange quarks. Our calculations are based on the dynamical domain-wall gauge field configurations generated by the RBC and UKQCD collaborations at a spatial volume of (2.7 fm)^3 and a range of quark masses with a lightest value corresponding to a (partially-quenched) pion mass of 275 MeV. When extrapolated to the physical values of the light quark masses, the results of our calculations are generally in good agreement with experimental determinations in the bottom sector. However, the static limit splittings between the Omega_b^- baryon and other bottom hadrons tend to slightly underestimate those obtained using the recent D-zero measurement of the Omega_b^-.