The DM approach to semileptonic heavy-to-heavy and heavy-to-light $B$ decays

TL;DR

This paper applies the Dispersion Matrix approach to determine hadronic form factors in semileptonic B-meson decays, enabling non-perturbative, model-independent analysis across the entire kinematic range to extract CKM matrix elements and test lepton flavor universality.

Contribution

It introduces the Dispersion Matrix method for form factor determination, avoiding parameterization, and applies it to extract CKM elements and lepton universality ratios from various B-meson decay channels.

Findings

Form factors determined across full kinematic range without parameterization.

New estimates of CKM matrix elements |V_cb| and |V_ub|.

Updated lepton flavor universality ratios for B decays.

Abstract

We present the results of the application of the Dispersion Matrix approach to semileptonic heavy-to-heavy and heavy-to-light $B$-meson decays. This method allows to determine the hadronic form factors in a non-perturbative and model-independent way. Starting from the available lattice results at large values of the momentum transfer, we obtain the behaviour of the form factors in their whole kinematical range without introducing any parameterization of their momentum dependence. We will focus on the determination of the Cabibbo-Kobayashi-Maskawa matrix elements $\vert V_{cb} \vert$ and $\vert V_{ub} \vert$ through the analysis of $B \to D^{(*)} \ell \nu$, $B_s \to D_s^{(*)} \ell \nu$, $B \to \pi \ell \nu$ and $B_s \to K \ell \nu$ decays. New theoretical determinations of the Lepton Flavour Universality ratios relevant for these transitions will be also presented, by focusing in particular on the $R(D_{(s)}^{(*)})$ ratios.