Search

Lattice QCD with exact chiral symmetry is an ideal theoretical framework to study the non-perturbative physics from the first principles of QCD. Howev er, it is rather nontrivial to performMonte Carlo simulation such that the chiral symmetry is perserved to a very high precision and alltopological sectors are sampled ergodically.Since 2009, the Taiwan Lattice QCD Collaboration (TWQCD) has been using a GPU cluster(currently constituting of 250 NVIDIA GPUs) which attains 40 Teraflops (sustained) to simulateunquenched lattice QCD with the optimal domain-wall quarks[1, 2]. We have realized our goal ofpreserving the chiral symmetry to a good precision (with m

We present the first study of the masses and decay constants of the pseudoscalar $ D $ mesons in two flavors lattice QCD with domain-wall fermion. The gauge ensembles are generated on the $24^3 \times 48 $ lattice with the extent $ N_s = 16 $ in the fifth dimension, and the plaquette gauge action at $ \beta = 6.10 $, for three sea-quark masses with corresponding pion masses in the range $260-475$ MeV. We compute the point-to-point quark propagators, and measure the time-correlation functions of the pseudoscalar and vector mesons. The inverse lattice spacing is determined by the Wilson flow, while the strange and the charm quark masses by the masses of the vector mesons $ \phi(1020) $ and $ J/\psi(3097) $ respectively. Using heavy meson chiral perturbation theory (HMChPT) to extrapolate to the physical pion mass, we obtain $ f_D = 202.3(2.2)(2.6) $ MeV and $ f_{D_s} = 258.7(1.1)(2.9) $ MeV., Comment: 15 pages, 3 figures. v2: the statistics of ensemble (A) with m_sea = 0.005 has been increased, more details on the systematic error, to appear in Phys. Lett. B