We study an accurate method for the lattice calculation of the B*Bpi Coupling in the static limit, paying particular attention to excited state contamination. As this coupling is a parameter of the heavy meson chiral Lagrangian, it is useful for constraining the chiral behaviour of various observables in B-physics. We present a precise study of the continuum limit in the quenched approximation and preliminary results with 2 flavours of improved Wilson quarks (using CLS lattices) for pion masses down to around 250 MeV. With dynamical quarks both the lattice spacing and the light quark mass dependences are found to be very weak. We can quote g = 0.51(2) for the continuum value in the chiral limit, where the error will be reduced when a more complete analysis has been performed.
@article{arxiv.1011.4393,
title = {The B*Bpi Coupling in the Static Limit},
author = {J. Bulava and M. A. Donnellan and Rainer Sommer},
journal= {arXiv preprint arXiv:1011.4393},
year = {2011}
}
Comments
7 pages, 3 figures. Talk given at the XXVIII International Symposium on Lattice Field Theory (Lattice 2010), Villasimius, Italy, June 2010