https://doi.org/10.1140/epjc/s10052-015-3585-4
Regular Article - Theoretical Physics
Semileptonic 
decays in lattice QCD: a feasability study and first results
1
Laboratoire de Physique Théorique, Unité Mixte de Recherche 8627 du Centre National de la Recherche Scientifique et Université Paris-Sud XI, Bâtiment 210, 91405, Orsay Cedex, France
2
Laboratoire de Physique Corpusculaire de Clermont-Ferrand, Unité Mixte de Recherche 6533 CNRS/IN2P3, Université Blaise Pascal, Campus des Cézeaux, 24 avenue des Landais, BP 80026, 63171, Aubière Cedex, France
3
Inria Saclay, Bâtiment Alan Turing, 1 rue Honoré d’Estienne d’Orves, Campus de l’Ecole Polytechnique, 91120, Palaiseau, France
* e-mail: benoit.blossier@th.u-psud.fr
Received:
16
April
2015
Accepted:
30
July
2015
Published online:
21
August
2015
We compute the decays 
and 
with finite masses for the b and c quarks. We first discuss the spectral properties of both the B meson as a function of its momentum and the 
and 
at rest. We compute the theoretical formulae leading to the decay amplitudes from the three-point and two-point correlators. We then compute the amplitudes at zero recoil of , which turns out not to be vanishing contrary to what happens in the heavy quark limit. This opens the possibility to get better agreement with experiment. To improve the continuum limit we have added a set of data with smaller lattice spacing. The vanishes at zero recoil and we show a convincing signal but only slightly more than 1 sigma from 0. In order to reach quantitatively significant results we plan to exploit fully smaller lattice spacings as well as another lattice regularisation.
© The Author(s), 2015
