出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We present the results of a partially quenched lattice QCD calculation of light quark masses with
Nf = 2 degenerate dynamical flavors. Numerical simulations are carried out using the plaquette
gauge action and the Wilson quark action at b = 5:8 (a1 ' 3:2GeV). The spatial extension of
the 243 48 lattice is about 1.5 fm. Configurations have been generated at four values of the
sea quark masses, for which the ratio of pseudoscalar over vector meson masses is in the range
MP=MV ' 0:600:75. An important feature of the present study is the use of non-perturbative
renormalization, performed with the RI-MOM method. The effects of dynamical sea quarks
in the determination of light quark masses have been investigated by performing a quenched
calculation on a similar lattice. Our results for the average up-down and strange quark masses
are mMS
ud (2GeV) = 4:3(4)(+1:1
0:4)MeV and mMS
s (2GeV) = 101(8)(+25
9 )MeV. These values are
larger than those obtained by evaluating the quark mass renormalization constants with one-loop
(boosted) perturbation theory. Our results for the light quark masses are compatible with those
obtained in the quenched simulation. No significant sea quark effects are seen, at the values of
sea quark masses used in the present study.
