2+1 Flavor Light Hadron Spectrum And Quark Masses With The O(a) Improved Wilson-clover Quark Formalism

We present a summary of results of the joint CP-PACS and JLQCD project toward a 2+1 flavor full QCD simulation with the $O(a)$-improved Wilson quark formalism and the Iwasaki gauge action. Configurations were generated during 2002--2005 at three lattice spacings, $a\sim 0.076$, 0.100 and 0.122 fm, keeping the physical volume constant at $(2.0 {fm})^3$. Up and down quark masses are taken in the range $m_{PS}/m_V\sim0.6-0.78$. We have completed the analysis for the light meson spectrum and quark masses in the continuum limit using the full configuration set. The predicted meson masses reproduce experimental values in the continuum limit at a 1% level. The average up and down, and strange quark masses turn out to be $m_{ud}^{\bar{\rm MS}}(\mu=2 {\rm GeV})=3.50(14)({}^{+26}_{-15}) {\rm MeV}$ and $m_s^{\bar{\rm MS}}(\mu=2 {\rm GeV})=91.8(3.9)({}^{+6.8}_{-4.1}) {\rm MeV}$. We discuss our future strategy toward definitive results on hadron spectroscopy with the Wilson-clover formalism