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arXiv · hep-lat/9609046

Light Quark Masses and the CP violation parameter $ε'/ε$

R. Gupta·T. Bhattacharya
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Abstract

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 MSbar scheme at scale $2 GeV$, are $mbar=3.2(4) MeV$ and $m_s = 90(20) MeV$ in the quenched approximation, and $mbar ~ 2.7 MeV$ and $m_s ~ 70 MeV$ 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. Along with the new estimates of 4-fermion operators, lower quark masses have a significant impact on the extraction of $ε'/ε$ from the Standard Model.

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R. Gupta, T. Bhattacharya. 1996-09-28. Light Quark Masses and the CP violation parameter $ε'/ε$. https://doi.org/10.1016/s0920-5632(96)00640-8

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