Oct 2020 - Sept 2021

# External Seminar by Bernat Capdevila

Europe/London
Description

Title:

## Inclusive semileptonic $B$-meson decays $B\to X_u\ell\nu$ and $V_{ub}$ determinations: challenges and theoretical framework(s)

Abstract:

The CKM matrix is a key ingredient in the study of CP violation and in New Physics searches within the flavour sector. Therefore, precise determinations of their elements are of utmost importance. The matrix element $|V_{ub}|$ can be extracted from both exclusive semileptonic $b\to u$ decays, mainly $B\to\pi\ell\nu$, and the inclusive charmless channels $B\to X_u\ell\nu$. These two types of $|V_{ub}|$ determinations have been in tension for a long time and the different theoretical frameworks used to describe $B\to X_u\ell\nu$ decays lead to values of $|V_{ub}|$ that do not agree well with one another. In this seminar, I am going to review the techniques employed in the study of inclusive semileptonic $B$-meson decays, with emphasis on the challenges faced to obtain a solid description of $B\to X_u\ell\nu$ and some of the solutions proposed. I will also present the first calculation of perturbative power suppressed corrections to the hadronic tensor that parametrises the triple differential decay distribution of these inclusive decays, whose non-trivial effects will impact the determination of $|V_{ub}|$ in forthcoming analyses, and discuss some simple applications.

Zoom link:  IPPP Seminars (Thursday at 2 pm UK time)

https://durhamuniversity.zoom.us/j/99420124988?pwd=ZEFLSDB3THJtaWZOTU54R25mT1NuZz09

Meeting ID: 994 2012 4988