1209.6115 (Shoichi Sasaki)

Hyperon vector form factor from 2+1 flavor lattice QCD    [PDF]

Shoichi Sasaki

We present the first result for the hyperon vector form factor f_1 for Xi^0 -> Sigma^+ l bar{nu} and Sigma^- -> n l bar{nu} 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 1/a=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 predictions of both the latest baryon chiral perturbation theory result and large N_c analysis.

View original: http://arxiv.org/abs/1209.6115