We present a lattice NRQCD study of the B meson decay constant in the quenched approximation with emphasis given to the scaling behavior. The NRQCD action and the heavy-light axial current we use include all terms of order 1/M and the perturbative O(αsa) and O(αs/M) corrections. Using simulations at three value of couplings β=5.7, 5.9 and 6.1 on lattices of size 123×32,163×48 and 243×64, we find no significant a dependence in fB if the O(αsa) correction is included in the axial current. We obtain fB=167(7)(15) MeV, fBs=191(4)(17)(−0+4) MeV and fBs/fB=1.15(3)(1)(−0+3), with the first error being statistical, the second systematic, and the third due to uncertainty of strange quark mass, while quenching errors being not included.
@article{arxiv.hep-lat/9905036,
title = {B meson leptonic decay constant with quenched lattice NRQCD},
author = {JLQCD Collaboration and K-I. Ishikawa and N. Yamada and S. Aoki and M. Fukugita and S. Hashimoto and N. Ishizuka and Y. Iwasaki and K. Kanaya and T. Kaneda and S. Kaya and Y. Kuramashi and H. Matsufuru and M. Okawa and T. Onogi and S. Tominaga and N. Tsutsui and A. Ukawa and T. Yoshié},
journal= {arXiv preprint arXiv:hep-lat/9905036},
year = {2009}
}