Differential decay rate for $B \to \pi l \nu$ semileptonic decays

TL;DR

This paper calculates the differential decay rate for the semileptonic decay $B o \pi l u$ using lattice QCD with NRQCD for heavy quarks, providing model-independent predictions and insights into form factors.

Contribution

The study offers a lattice QCD calculation of $B o \pi l u$ form factors with small $1/m_B$ corrections, enabling direct prediction of decay rates without model assumptions.

Findings

Small $1/m_B$ correction to form factors

Model-independent prediction of $d\Gamma/dq^2$

Discussion of soft pion limit effects

Abstract

We present our study on $B \to \pi l \nu$ semileptonic decay form factors with NRQCD action for heavy quark from a quenched lattice QCD simulation at $\beta$=5.9 on a $16^3\times 48$ lattice. We obtain form factors defined in the context of heavy quark effective theory by Burdman et al. and find that their $1/m_B$ correction is small. The limit of physical heavy and light quark masses can be performed without introducing any model function, and we obtain a prediction for the differential decay rate $d\Gamma/dq^2$. We also discuss the soft pion limit of the form factors.