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arXiv · 1312.2914

Semileptonic $B \to D^{**}$ decays in Lattice QCD : a feasibility study and first results

M. Atoui·B. Blossier·V. Morénas·O. Pène·K. Petrov
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Abstract

We compute the decays ${B\to D^\ast_0}$ and ${B\to D^\ast_2}$ 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 of the $D^\ast_0$ and $D^\ast_2$ 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 ${B\to D^\ast_0}$ which turns out not to be vanishing contrary to what happens in the heavy quark limit. This opens a possibility to get a better agreement with experiment. To improve the continuum limit we have added a set of data with smaller lattice spacing. The ${B\to D^\ast_2}$ 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 fully exploit smaller lattice spacings as well as another lattice regularization.

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M. Atoui, B. Blossier, V. Morénas, O. Pène, K. Petrov. 2013-12-10. Semileptonic $B \to D^{**}$ decays in Lattice QCD : a feasibility study and first results. https://arxiv.org/abs/1312.2914

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