HQET at order 1/m: III. Decay constants in the quenched approximation

Benoît Blossier (1) , Michele Della Morte (2) , Nicolas Garron (3, 4) , Georg von Hippel (5) , Tereza Mendes (5, 6) , Hubert Simma (3) , Rainer Sommer (5)

1 LPT - Laboratoire de Physique Théorique d'Orsay [Orsay]
2 Institut für Kernphysik
3 Dpto Fisica Teorica and Instituto de Fisica Teorica UAM/CSIC
4 SUPA School of Physics and Astronomy [Edinburgh]
5 DESY - Deutsches Elektronen-Synchrotron [Zeuthen]
6 Physics Department

We report on the computation of the $B_s$ meson decay constant in Heavy Quark Effective Theory on the lattice. The next to leading order corrections in the HQET expansion are included non-perturbatively. We estimate higher order contributions to be very small. The results are extrapolated to the continuum limit, the main systematic error affecting the computation is therefore the quenched approximation used here. The Generalized Eigenvalue Problem and the use of all-to-all propagators are important technical ingredients of our approach that allow to keep statistical and systematic errors under control. We also report on the decay constant $f_{B'_s}$ of the first radially excited state in the $B_s$ sector, computed in the static limit.

Domaines: Physique des Hautes Energies - Réseau [hep-lat]

Benoît Blossier, Michele Della Morte, Nicolas Garron, Georg von Hippel, Tereza Mendes, et al.. HQET at order 1/m: III. Decay constants in the quenched approximation. Journal of High Energy Physics, 2010, 12, pp.039. ⟨10.1007/JHEP12(2010)039⟩. ⟨hal-00534828⟩