Indirect bounds on new physics for $R(D^{(*)})$

TL;DR

This paper proposes a new method using operator product expansion to more accurately compute the $B_c$ meson lifetime by canceling out free-quark contributions, thus reducing theoretical uncertainties.

Contribution

It introduces a novel approach based on differences of decay rates to improve the precision of $B_c$ lifetime predictions within the Standard Model.

Findings

New method reduces uncertainties in $B_c$ lifetime calculations

Operator product expansion applied to meson decay rate differences

Enhanced understanding of $B_c$ lifetime within the Standard Model

Abstract

The Standard Model prediction of the $B_c$ lifetime is discussed, together with the dominant uncertainties and strategies on how to improve them. Furthermore, a new method to compute the $B_c$ lifetime based on the operator product expansion is proposed. It relies on differences of $B,\,D$ and $B_c$ meson decay rates, in which the free-quark contributions cancel out, reducing the uncertainty of the theory prediction.