The electromagnetic form factors of the Omega in lattice QCD

TL;DR

This paper computes the electromagnetic form factors of the Omega baryon using lattice QCD with dynamical quarks, providing new insights into its magnetic moment, charge radius, and electric quadrupole moment.

Contribution

It presents the first determination of the Omega baryon's electric quadrupole moment using dynamical quarks and compares different lattice fermion formulations.

Findings

Omega^- magnetic moment measured with high precision.

Electric charge and magnetic radii extracted for the first time.

Electric quadrupole moment determined, excluding zero value.

Abstract

We present results on the Omega baryon electromagnetic form factors using $N_f=2+1$ domain-wall fermion configurations for three pion masses in the range of about 350 to 300 MeV. We compare results obtained using domain wall fermions with those of a mixed-action (hybrid) approach, which combine domain wall valence quarks on staggered sea quarks, for a pion mass of about 350 MeV. We pay particular attention in the evaluation of the subdominant electric quadrupole form factor to sufficient accuracy to exclude a zero value, by constructing a sequential source that isolates it from the dominant form factors. The $\Omega^-$ magnetic moment, $\mu_{\Omega^{-}}$, the electric charge and magnetic radius, $\langle r^{2}_{E0/M1} \rangle$, are extracted for these pion masses. The electric quadrupole moment is determined for the first time using dynamical quarks.