出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We report on the PACS-CS project focusing on a direct simulation of 2+1 avor QCD on the
physical point and chiral analysis of meson and baryon masses off the physical point with both
the SU(2) and SU(3) chiral perturbation theories. Congurations are generated with the O(a)-
improved Wilson quark action and the Iwasaki gauge action. The up-down quark is simulated
by employing the DDHMC algorithm with several improvements and the UV-ltered PHMC
algorithm is implemented for the strange quark. We investigate the convergence behaviors of the
SU(2) and SU(3) chiral expansions up to NLO for the pseudoscalar meson sector, where the updown
quark mass ranges from 3 MeV to 24 MeV and the strange quark mass is chosen around
the physical value. The t results for the low energy constants are compared with those recently
obtained by other groups. We also discuss the importance of the direct simulation at the physical
point by comparing the physical quantities measured on the physical point with those estimated
by the extrapolation method.
