Elementary Particles on a Dedicated Parallel Computer

Abstract

Numerical simulation of lattice QCD is now an indispensable tool for investigating non-perturbative properties of quarks at low energies. In this paper, I introduce a recent lattice QCD calculation of light hadron spectrum and quark masses performed on a dedicated parallel computer, CP-PACS. From a simulation of QCD with two flavors of dynamical quarks, we find $m_{ud}^{\overline{\mathrm{MS}}}(2\mathrm{GeV})=3.44_{-0.22}^{+0.14}$ MeV for the averaged mass of $u$ and $d$ quarks to reproduce the experimental masses of $\pi$ and $\rho$ mesons, and $m_s^{\overline{\mathrm{MS}}}(2\mathrm{GeV})=88_{-6}^{+4}$ MeV or $90_{-11}^{+5}$ MeV to reproduce the $K$ or $\varphi$ meson mass. These values are about 20--30% smaller than the previous estimates using the quenched approximation.

Comments: Talk presented at the 18th AvH symposium ``100 Years Werner Heisenberg - Works and Impact'', Bamberg, Germany, September 26-30, 2001. 7 pages, 4 PS figures, buckow.sty needed