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arXiv · 1404.3590

Decay constants of B-mesons from non-perturbative HQET with two light dynamical quarks

F. Bernardoni·B. Blossier·J. Bulava·M. Della Morte·P. Fritzsch·N. Garron·A. Gérardin·J. Heitger·G. von Hippel·H. Simma·R. Sommer
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Abstract

We present a computation of B-meson decay constants from lattice QCD simulations within the framework of Heavy Quark Effective Theory for the b-quark. The next-to-leading order corrections in the HQET expansion are included non-perturbatively. Based on Nf=2 gauge field ensembles, covering three lattice spacings a (0.08-0.05)fm and pion masses down to 190MeV, a variational method for extracting hadronic matrix elements is used to keep systematic errors under control. In addition we perform a careful autocorrelation analysis in the extrapolation to the continuum and to the physical pion mass limits. Our final results read fB=186(13)MeV, fBs=224(14)MeV and fBs/fB=1.203(65). A comparison with other results in the literature does not reveal a dependence on the number of dynamical quarks, and effects from truncating HQET appear to be negligible.

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F. Bernardoni, B. Blossier, J. Bulava, M. Della Morte, P. Fritzsch, N. Garron, A. Gérardin, J. Heitger, G. von Hippel, H. Simma, R. Sommer. 2014-04-14. Decay constants of B-mesons from non-perturbative HQET with two light dynamical quarks. https://doi.org/10.1016/j.physletb.2014.06.051

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