The decay constants fD and {f}_{D_s} in the continuum limit of Nf = 2 + 1 domain wall lattice QCD

Abstract

We present results for the decay constants of the D and Ds mesons computed in lattice QCD with Nf = 2 + 1 dynamical flavours. The simulations are based on RBC/UKQCD’s domain wall ensembles with both physical and unphysical light-quark masses and lattice spacings in the range 0.11-0.07 fm. We employ the domain wall discretisation for all valence quarks.The results in the continuum limit are fD = 208.7(2.8)stat(− 1.8+ 2.1)sysMeV and {f}_{D_s}=246.4{(1.3)}_{mathrm{stat}}{left({}_{-1.9}^{+1.3}right)}_{mathrm{sys}}mathrm{M}mathrm{e}mathrm{V} and {f}_{D_s}={f}_D=1.667{(77)}_{mathrm{stat}}{left({}_{-43}^{+57}right)}_{mathrm{sys}} . Using these results in a Standard Model analysis we compute the predictions |Vcd| = 0.2185(50)exp(− 37+ 35)lat and |Vcs| = 1.011(16)exp(− 9+ 4)lat for the CKM matrix elements.