Nonperturbative Renormalization in the RI-SMOM Scheme and Gribov Uncertainty in the RI-MOM Scheme for Staggered Bilinears

We present results of renormalization factors for bilinear operators obtained using the nonperturbative renormalization method (NPR) in the RI-SMOM schemes. The operators are constructed using HYP staggered quarks on the MILC asqtad lattice ($N_f=2+1$). We compare results in the RI-SMOM schemes with those in the RI-MOM scheme for the $V\otimes S$ and $S\otimes S$ operators. Since we use Landau gauge fixing, we study the effect of Gribov ambiguity on the wave function renormalization $Z_q$ in the RI-MOM scheme. We find that the Gribov uncertainty is negligibly small for $Z_q$ in the RI-MOM scheme.