LIGHT QUARK MASSES AND THE CP VIOLATION PARAMETER EPSILON'/EPSILON

摘要

We present estimates of light quarks masses using lattice data. Our main results are based on a global analysis of all the published data for Wilson and Staggered fermions, both in the quenched approximation and with n(f) = 2 dynamical flavors. The Wilson and Staggered results agree after extrapolation to the continuum limit for both the n(f) = 0, 2 theories. Our best estimates, in the <(MS)over bar> scheme at scale 2 GeV, are (m) over bar = 3.2(4) MeV and m(s) = 90(20) MeV in the quenched approximation, and (m) over bar similar to 2.7 MeV and (m) over bar similar to 70 MeV for the n(f) = 2 theory. These estimates are significantly smaller than phenomenological estimates based on sum rules, but maintain the ratios predicted by chiral perturbation theory (chi PT). Along with the new estimates of 4-fermion operators, lower quark masses have a significant impact on the extraction of epsilon'/epsilon from the Standard Model. [References: 8]