The $B_c$ lifetime in the Standard Model

TL;DR

This paper provides an updated Standard Model prediction for the $B_c$ meson lifetime using an operator product expansion approach, comparing different mass schemes and introducing a novel decay rate difference method to reduce theoretical uncertainties.

Contribution

It introduces a new method for calculating the $B_c$ lifetime by using decay rate differences, minimizing scale and scheme dependence, and compares multiple mass schemes for consistency.

Findings

Predictions are consistent across three mass schemes and with experimental data.

The novel decay difference method reduces theoretical uncertainties.

The approach offers a more robust calculation of the $B_c$ lifetime.

Abstract

Using an operator product expansion (OPE) approach an updated Standard Model prediction of the $B_c$ lifetime is presented. The computation in three different mass schemes for the heavy quarks leads to three different values consistent with each other and with experiment. Furthermore a novel way to compute the $B_c$ lifetime is presented, taking differences of $B,D$ and $B_c$ meson decay rates. In this approach the leading contributions from free-quark decays cancel out, leading to a reduction of scale and scheme dependence.