First Nonperturbative Test of a Relativistic Heavy Quark Action in   Quenched Lattice QCD
  We perform a numerical test of a relativistic heavy quark(RHQ) action, recently proposed by Tsukuba group, in quenched lattice QCD at $a\simeq 0.1$ fm. With the use of the improvement parameters previously determined at one-loop level for the RHQ action, we investigate a restoration of rotational symmetry for heavy-heavy and heavy-light meson systems around the charm quark mass. We focused on two quantities, the meson dispersion relation and the pseudo-scalar meson decay constants. It is shown that the RHQ action significantly reduces the discretization errors due to the charm quark mass. We also calculate the S-state hyperfine splittings for the charmonium and charmed-strange mesons and the $D_s$ meson decay constant. The remaining discretization errors in the physical quantities are discussed. 
Y. Kayaba, S. Aoki, M. Fukugita, Y. Iwasaki, K. Kanaya, Y. Kuramashi,   M. Okawa, A. Ukawa and T.Yoshie (CP-PACS Collaboration)