RI/MOM and RI/SMOM renormalization of quark bilinear operators using overlap fermions

TL;DR

This study computes vector, scalar, and tensor renormalization constants for overlap fermions using RI/MOM and RI/SMOM schemes across various lattice spacings, highlighting their consistency with the MSbar scheme and the impact of nonperturbative effects at certain momenta.

Contribution

It provides a detailed comparison of RI/MOM and RI/SMOM renormalization schemes for overlap fermions on the lattice, including their dependence on lattice spacing and sea quark actions.

Findings

RI/MOM and RI/SMOM yield consistent RCs with MSbar after extrapolation.

Nonperturbative effects are significant at around 2 GeV momenta.

Renormalization constants are sensitive to lattice spacing but not to the bare gauge coupling.

Abstract

We present the vector, scalar and tensor renormalization constants (RCs) using overlap fermions with either regularization independent momentum subtraction (RI/MOM) or symmetric momentum subtraction (RI/SMOM) as the intermediate scheme on the lattice with lattice spacings $a$ from 0.04 fm to 0.12 fm. Our gauge field configurations from the MILC and RBC/UKQCD collaborations include sea quarks using either the domain wall or the HISQ action, respectively. The results show that RI/MOM and RI/SMOM can provide consistent renormalization constants to the $\overline{\textrm{MS}}$ scheme, after proper $a^2p^2$ extrapolations. But at $p\sim 2$\,GeV, both RI/MOM and RI/SMOM suffer from nonperturbative effects which cannot be removed by the perturbative matching. The comparison between the results with different sea actions also suggests that the renormalization constant is discernibly sensitive to the lattice spacing but not to the bare gauge coupling in the gauge action.