A lattice measurement of the B*B? coupling using DWF light quarks and the Relativistic Heavy Quark action

I describe a calculation of the B*B? coupling in lattice QCD. The B*B? coupling is directly related to gb, the leading order low-energy interaction constant of heavy meson chiral perturbation theory. Knowledge of the coupling will help decrease systematic uncertainties in lattice QCD B-physics studies, which are important to constrain the CKM matrix and probe the Standard Model. This calculation is performed with 2+1 flavours of dynamic quarks using the domain wall fermion action. To simulate the heavy b-quark I use a non-perturbatively tuned relativistic heavy quark action which keeps discretisation effects under good control. This allows me to make the first calculation of theB*B? coupling directly at the physical b-quark mass. I conduct a chiral and continuum extrapolation to the physical point and consider all sources of systematic error. The final result including both statistical and sytematic errors is gb = 0.567(52)stat(58)sys