Calculations of pseudoscalar decay constants of B, Bs, K and pi mesons with physical light quarks are presented. We use HISQ ensembles that include u,d,s and c sea quarks at three lattice spacings. HISQ is used for the valence light quarks and a radiatively improved NRQCD action for the heavy quarks. The key results are f_{B^+}=0.184(4)$ GeV, f_{B_s}=0.224(4) GeV, f_{B_s}/f_{B^+}=1.217(8), f_{K^+}/f_{pi^+}=1.1916(21), f_{K^+}=155.37(34) MeV, giving a significant improvement over previous results that required chiral extrapolation. We also calculate the Wilson flow scale w_0, finding w_0=0.1715(9) fm.
@article{arxiv.1309.4610,
title = {B, Bs, K and pi weak matrix elements with physical light quarks},
author = {R. J. Dowdall and C. T. H. Davies and R. R. Horgan and G. P. Lepage and C. McNeile and C. J. Monahan and J. Shigemitsu},
journal= {arXiv preprint arXiv:1309.4610},
year = {2013}
}
Comments
7 pages, 8 figures, presented at the 31st International Symposium on Lattice Field Theory