Hyperon vector form factor from 2+1 flavor lattice QCD

We present the first result for the hyperon vector form factor f(1) for Xi(0) -> Sigma(+)l (v) over bar and Sigma(=)-> nl (v) over bar semileptonic decays from fully dynamical lattice QCD. The calculations are carried out with gauge configurations generated by the RBC and UKQCD collaborations with (2 + 1)-flavors of dynamical domain-wall fermions and the Iwasaki gauge action at beta = 2.13, corresponding to a cutoff a(-1) = 1.73 GeV. Our results, which are calculated at the lighter three sea quark masses (the lightest pion mass down to approximately 330 MeV), show that a sign of the second-order correction of SU(3) breaking on the hyperon vector coupling f(1)(0) is negative. The tendency of the SU(3)-breaking correction observed in this work disagrees with predictions of both the latest baryon chiral perturbation theory result and large N-c analysis.