Semileptonic decays of $B^{(*)}$, $D^{(*)}$ into ${\nu} l$ and pseudoscalar or vector mesons

TL;DR

This paper introduces a novel method for calculating semileptonic decay rates of B and D mesons, simplifying the process and accurately predicting multiple decay modes with minimal experimental input.

Contribution

The study develops a new approach using spin-angular momentum algebra to evaluate decay matrix elements, enabling predictions of decay rates from limited experimental data.

Findings

Predicted decay rates align well with experimental data.

Identified and explained discrepancies in tau decay modes.

Provided decay rate predictions for B* and D* mesons for future experiments.

Abstract

We perform a study of the $B^{(*)}$, $D^{(*)}$ semileptonic decays, using a different method than in conventional approaches, where the matrix elements of the weak operators are evaluated and a detailed spin-angular momentum algebra is performed to obtain very simple expressions at the end for the different decay modes. Using only one experimental decay rate in the $B$ or $D$ sectors, the rates for the rest of decay modes are predicted and they are in good agreement with experiment. Some discrepancies are observed in the $\tau$ decay mode for which we find an explanation. We perform evaluations for $B^*$ and $D^*$ decay rates that can be used in future measurements, now possible in the LHCb collaboration.