Theory overview of tree-level $B$ decays

TL;DR

This paper reviews recent theoretical progress in semileptonic tree-level B decays, focusing on anomalies in decay ratios and CKM element determinations, and discusses potential explanations and tests for these discrepancies.

Contribution

It provides an overview of theoretical developments and discusses possible explanations for anomalies in B decay measurements and their implications.

Findings

Discussion of anomalies in $R(D^{(*)})$ ratios.

Analysis of inclusive vs exclusive $|V_{cb}|$ determinations.

Proposed tests to investigate the anomalies' origins.

Abstract

I describe the theoretical progress in the study of semileptonic tree-level B decays, and its interplay with recent experimental results. In particular, I focus on two anomalies: the ratios $R(D^{(*)})=\displaystyle\frac{{\cal B}(B \to D^{(*)} \tau \bar \nu_\tau)}{{\cal B}(B \to D^{(*)} \ell \bar \nu_\ell)}$ and the inclusive versus exclusive determination of $|V_{cb}|$. I review a few explanations proposed for such anomalies, and discuss tests to shed light on their origin.