Light Quark Masses with Overlap Fermions in Quenched QCD

TL;DR

This paper computes light quark masses using overlap fermions in quenched QCD, achieving improved accuracy by preserving chiral symmetry and non-perturbative renormalization, resulting in precise estimates of quark masses and condensates.

Contribution

It introduces a method using overlap fermions in quenched QCD that avoids additive mass renormalization and achieves O(a) improvement, with non-perturbative renormalization for accurate quark mass determination.

Findings

Quark masses are determined with reduced systematic errors.

Results are consistent with previous estimates within uncertainties.

Non-perturbative renormalization enhances the reliability of the results.

Abstract

We present the results of a computation of the sum of the strange and average up-down quark masses with overlap fermions in the quenched approximation. Since the overlap regularization preserves chiral symmetry at finite cutoff and volume, no additive quark mass renormalization is required and the results are O(a) improved. Our simulations are performed at beta=6.0 and volume V=16^3X32, which correspond to a lattice cutoff of ~2 GeV and to an extension of ~1.4 fm. The logarithmically divergent renormalization constant has been computed non-perturbatively in the RI/MOM scheme. By using the K-meson mass as experimental input, we obtain (m_s + m_l)^RI(2 GeV) = 120(7)(21) MeV, which corresponds m_s^MS (2 GeV) = 102(6)(18) MeV if continuum perturbation theory and ChiPT are used. By using the GMOR relation we also obtain <psi psi>^MS(2 GeV)/N_f = - 0.0190(11)(33) GeV^3 = - [267(5)(15) MeV]^3.