The electromagnetic form factors of the Omega in lattice QCD

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, $⟨r_{E0/M1}^2⟩$, are extracted for these pion masses. The electric quadrupole moment is determined for the first time using dynamical quarks.

Comments: 13 pages, 10 Figures