Pseudoscalar decay constants fD and fDs, in lattice QCD with exact chiral symmetry

We determine the masses and decay constants of pseudoscalar mesons D, D-s, and K in quenched lattice QCD with exact chiral symmetry. For 100 gauge configurations generated with single-plaquette action at beta = 6.1 on the 20(3) x 40 lattice, we compute point-to-point quark propagators for 30 quark masses in the range 0.03 <= m(q)a <= 0.80, and measure the time-correlation functions of pseudoscalar and vector mesons. The inverse lattice spacing a(-1) is determined with the experimental input of f(pi), while the strange quark bare mass m(s)a = 0.08, and the charm quark bare mass m(c)a = 0.80 are fixed such that the masses of the corresponding vector mesons are in good agreement with phi(1020) and J/Psi(3097), respectively. Our results of pseudoscalar-meson decay constants are f(K) = 152(6)(10) MeV, f(D) = 235(8)(14) MeV, and fD(s) = 266(10)(18) MeV. (c) 2005 Elsevier B.V. All rights reserved.