Charm physics with overlap fermions on 2+1-flavor domain wall fermion configurations

Decay constants of pseudoscalar mesons D, D_s, η_c and vector mesons D^*, D_s^*, J/ψ are determined from N_f=2+1 lattice QCD at a lattice spacing a∼0.08 fm. For vector mesons, the decay constants defined by tensor currents are given in the MS scheme at 2 GeV. The calculation is performed on domain wall fermion configurations generated by the RBC-UKQCD Collaborations and the overlap fermion action is used for the valence quarks. Comparing the current results with our previous ones at a coarser lattice spacing a∼0.11 fm gives us a better understanding of the discretization error. We obtain f_D_s^*^T( MS,2 GeV)/f_D_s^*=0.907(20) with a better precision than our previous result. Combining our f_D_s^*=277(11) MeV with the total width of D_s^* determined in a recent work gives a branching fraction 4.26(52)×10^-5 for D_s^* leptonic decay.