Heavy+light pseudoscalar meson semileptonic transitions

TL;DR

This paper develops a simple, symmetry-preserving model to study semileptonic transitions of various mesons, providing predictions consistent with experimental and theoretical data, and offering insights into Higgs coupling effects.

Contribution

It introduces a unified, algebraically simple framework for treating semileptonic meson transitions across light and heavy systems, with predictions for unmeasured decay rates.

Findings

Results are comparable with experimental data and rigorous theory.

Predictions for unmeasured $B_{s,c}$ branching fractions.

Provides insights into Higgs coupling effects on form factors.

Abstract

A symmetry-preserving regularisation of a vector$\times$vector contact interaction (SCI) is used to deliver a unified treatment of semileptonic transitions involving $\pi$, $K$, $D_{(s)}$, $B_{(s,c)}$ initial states. The framework is characterised by algebraic simplicity, few parameters, and the ability to simultaneously treat systems from Nambu-Goldstone modes to heavy+heavy mesons. Although the SCI form factors are typically somewhat stiff, the results are comparable with experiment and rigorous theory results. Hence, predictions for the five unmeasured $B_{s,c}$ branching fractions should be a reasonable guide. The analysis provides insights into the effects of Higgs boson couplings via current-quark masses on the transition form factors; and results on $B_{(s)}\to D_{(s)}$ transitions yield a prediction for the Isgur-Wise function in fair agreement with contemporary data.