title: Dynamical quark effects on light quark masses
abstract: Light quark masses are calculated in lattice QCD with two degenerate flavors of dynamical quarks. The calculations are made with improved actions with lattice spacing a = 0.22-0.11 fm. In the continuum limit we find m(M&Smacr;)(ud)(2 GeV) = 3.44(+0.14)(-0.22) MeV using the pi and rho meson masses as physical input, and m(M&Smacr;)(s)(2 GeV) = 88(+4)(-6) MeV or 90(+5)(-11) MeV with the K or straight phi meson mass as additional input. The quoted errors represent statistical and systematic combined, the latter including those from continuum and chiral extrapolations, and from renormalization factors. Compared to quenched results, two flavors of dynamical quarks reduce quark masses by about 25%.
authors.affiliation: Center for Computational Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan.
authors.initials: AA
authors.lastname: Khan
authors.initials: S
authors.lastname: Aoki
authors.initials: G
authors.lastname: Boyd
authors.initials: R
authors.lastname: Burkhalter
authors.initials: S
authors.lastname: Ejiri
authors.initials: M
authors.lastname: Fukugita
authors.initials: S
authors.lastname: Hashimoto
authors.initials: N
authors.lastname: Ishizuka
authors.initials: Y
authors.lastname: Iwasaki
authors.initials: K
authors.lastname: Kanaya
authors.initials: T
authors.lastname: Kaneko
authors.initials: Y
authors.lastname: Kuramashi
authors.initials: T
authors.lastname: Manke
authors.initials: K
authors.lastname: Nagai
authors.initials: M
authors.lastname: Okawa
authors.initials: HP
authors.lastname: Shanahan
authors.initials: A
authors.lastname: Ukawa
authors.initials: T
authors.lastname: Yoshie