High precision study of B*B pi coupling in unquenched QCD

TL;DR

This study precisely calculates the B*B pi coupling in unquenched QCD using lattice simulations, which is crucial for understanding heavy-light meson interactions and improving the determination of the CKM matrix element |Vub|.

Contribution

It presents a high-precision lattice QCD calculation of the B*B pi coupling with unquenched data, employing advanced techniques like all-to-all propagators and HYP smearing.

Findings

Accurate B*B pi coupling value obtained.

Enhanced statistical accuracy through improved methods.

Results support better constraints on |Vub|.

Abstract

The B* B pi coupling is a fundamental parameter of chiral effective Lagrangian with heavy-light mesons and can constrain the B->pi l nu form factor in the soft pion limit which will be useful for precise determination of |Vub|. We compute the B* B pi coupling with the static heavy quark and the O(a)-improved Wilson light quark. Simulations are carried out with n_f=2 unquenched 12^3x24 lattices at beta=1.80 generated by CP-PACS collaboration. Following the quenched study by Negishi et al., we employ the all-to-all propagator with 200 low eigenmodes as well as HYP smeared link to improve the statistical accuracy.