B-meson physics from non-perturbative lattice heavy quark effective theory

TL;DR

This paper discusses non-perturbative lattice HQET methods developed by the ALPHA collaboration to accurately compute B-meson properties, including recent progress with dynamical sea quarks and preliminary results.

Contribution

It introduces a non-perturbative matching approach in lattice HQET for B-meson observables, advancing beyond the static approximation with dynamical quarks.

Findings

Precise computation of b-quark mass and B-meson decay constants

Implementation of non-perturbative matching in lattice HQET

Progress in including sea quark effects with Nf=2

Abstract

During the last years, the ALPHA collaboration has been developing and implementing a method based on Heavy Quark Effective Theory (HQET) to compute B-mesons observables through lattice simulations. Thanks to a non-perturbative matching to QCD, the theory is renormalizable at any order of the heavy quark mass expansion. In order to extract precisely the relevant matrix elements and masses, we use all-to-all propagators and solve an generalized eigenvalue problem (GEVP). We have shown in the quenched approximation that quantities like the b-quark mass mb, the heavy-light decay constant(s) or the B-meson spectrum can be computed precisely beyond the static approximation (including the first corrections in 1/\mb). More recently, we have started to include the sea quark effects, by working with Nf=2 light flavors of dynamical fermions[1]. The computation of the matching parameters is almost finished, but concerning the extraction of the hadronic quantities for which we use some CLS ensembles[2], only one lattice spacing has been analyzed so far. In this proceeding we report on the status of this project and present some preliminary results.