Leptonic and semi-leptonic B decays

TL;DR

This paper reports lattice QCD calculations of leptonic and semi-leptonic B meson decays, providing key non-perturbative matrix elements to help constrain the CKM matrix and test heavy quark symmetry.

Contribution

It presents new lattice QCD results for B meson decay constants and form factors using improved actions in the quenched approximation.

Findings

Decay constants and form factors calculated with improved lattice techniques.

Results support heavy quark symmetry relations.

Analysis of chiral and momentum dependence of form factors.

Abstract

We present results for the semi-leptonic and leptonic decays of B mesons. These non-perturbative matrix elements are important for constraining the CKM matrix. Results are presented for the pseudoscalar and vector decay constants, as well as flavour breaking ratios and heavy quark symmetry relations. We consider the chiral and momentum dependence of the semi-leptonic form factors of the decay B-> pi l nu and the soft pion relation (SPR) on the lattice. These calculations were performed in the quenched approximation at two values of the coupling with non-perturbatively order a improved action and currents.