出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We present the results of the lattice QCD calculation of the average up-down and strange quark
masses and of the light meson pseudoscalar decay constants, recently performed with Nf = 2
dynamical fermions by the ETM Collaboration. The simulation is carried out at a single value
of the lattice spacing with the twisted mass fermionic action at maximal twist, which guarantees
automatic O(a)-improvement of the physical quantities. Quark masses are renormalized
by implementing the non perturbative RI-MOM renormalization procedure. Our results for the
light quark masses are mMS
ud (2 GeV) = 3.85± 0.12±0.40 MeV, mMS
s (2 GeV) = 105±3 ±9
MeV and ms/mud = 27.3±0.3±1.2. We also obtain fK = 161.7±1.2±3.1 MeV and the ratio
fK/ fp = 1.227±0.009±0.024. From this ratio, by using the experimental determination of
G(K→mn¯m (g ))/G(p →mn¯m (g )) and the average value of |Vud| from nuclear beta decays, we obtain
|Vus| =0.2192(5)(45), in agreement with the determination from Kl3 decays and the unitarity
constraint.
