B meson leptonic decay constant with quenched lattice NRQCD

JLQCD Collaboration

Ishikawa Kenichi

Yamada N

Aoki S

Fukugita M

Hashimoto S

Ishizuka N

Iwasaki Y

Kanaya K

Kaneda T

Kaya S

Kuramashi Y

Matsufuru H

Okawa Masanori

Onogi T

Tominaga S

Tsutsui N

Ukawa A

Yoshie T

Physical Review D

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 vector current we use include all terms of order 1/M and the perturbative O(αsa) and O(αs/M) corrections. Using simulations at three values of couplings β=5.7, 5.9, and 6.1 on lattices of sizes 123×32, 163×48, and 243×64, we find a significant a dependence disappears in fB if the O(αsa) correction is included in the axial vector current. We observe that β=5.9-6.1 is the window where systematic errors are expected to be minimum within one-loop improved theory. Our final results are fB=170(5)(15) MeV, fBs=191(4)(17)(-0+4) MeV, and fBs/fB=1.12(2)(1)(-0+3), where the first error is statistical, the second is systematic, and the third is due to the uncertainty of the strange quark mass, while quenching errors are not included.

lattice NRQCD

B meson decay constant

Physics [ 420 ]

eng

American Physical Society

Copyright (c) 2000 American Physical Society

[ISSN] 1550-7998

[DOI] 10.1103/PhysRevD.61.074501

[DOI] http://dx.doi.org/10.1103/PhysRevD.61.074501