Semileptonic B Decays from an NRQCD/D234 Action

TL;DR

This paper investigates semileptonic B decays into pions using lattice QCD with improved actions, confirming previous form factor results and highlighting the need for lighter quark masses to reduce systematic errors.

Contribution

It applies an NRQCD/D234 lattice approach with constrained fitting to study B decays, providing results consistent with prior studies and emphasizing the importance of lighter quark masses.

Findings

Results agree with previous lattice determinations of form factors.

Major systematic error arises from chiral extrapolation to physical pion mass.

Future work should focus on lighter quark masses.

Abstract

Semileptonic, B --> pi, l nubar, decays are studied on quenched anisotropic lattices using tree-level tadpole improved Symanzik glue, NRQCD heavy quark and D234 light quark actions. Constrained fitting methods are applied to extract groundstate contributions to two-point and three-point correlators. We agree with previous lattice determinations of the form factors. The major source of systematic error here, as in previous work, comes from the chiral extrapolation to the physical pion mass. Future calculations must work at lighter quark masses to resolve this.