Beautiful Baryons from Lattice QCD

TL;DR

This study uses lattice QCD to calculate heavy baryon masses, specifically $ ext{Λ}_b$ and $ ext{Ξ}_b$, revealing how their mass splittings vary with light quark mass.

Contribution

It provides the first lattice QCD calculations of $ ext{Λ}_b$ and $ ext{Ξ}_b$ baryon masses using the quenched approximation, including analysis of mass splittings.

Findings

Mass of $ ext{Λ}_b$ is approximately 5.728 GeV.

Mass splitting between $ ext{Λ}_b$ and B-meson increases by about 20% with heavier light quarks.

Results highlight the dependence of baryon mass splittings on light quark mass.

Abstract

We perform a lattice study of heavy baryons, containing one ($\Lambda_b$) or two $b$-quarks ($\Xi_b$). Using the quenched approximation we obtain for the mass of $\Lambda_b$ $$ M_{\Lambda_b}= 5.728 \pm 0.144 \pm 0.018 {\rm GeV}.$$ The mass splitting between the $\Lambda_b$ and the B-meson is found to increase by about 20\% if the light quark mass is varied from the chiral limit to the strange quark mass.