A phenomenological model for radiative corrections in exclusive semileptonic B-meson decays to (pseudo)scalar final state mesons

TL;DR

This paper develops a phenomenological model and Monte Carlo tool to evaluate electromagnetic radiative corrections in exclusive semileptonic B-meson decays, crucial for precise CKM matrix element extraction.

Contribution

It introduces a new model and implementation for radiative corrections in semileptonic B decays, applicable across the full phase space with a focus on low-energy photons.

Findings

Quantifies electromagnetic correction effects on decay rates.

Provides a Monte Carlo tool for experimental analysis.

Identifies uncertainties due to model assumptions.

Abstract

Next-to-leading order corrections are an important aspect in the extraction of the Cabibbo- Kobayashi-Maskawa matrix elements $|V_{\text{cb}}|$ and $|V_{\text{ub}}|$ at $B$-factory experiments: virtual and real photons couple to all charged particles of the decay, alter the resulting decay dynamics and enhance the total decay rate. We present a phenomenologically motivated model and a Monte-Carlo implementation to study electromagnetic radiative corrections to differential and total decay rates for semileptonic $B$-meson decays into exclusive pseudoscalar and scalar final states and apply it to $B \to D \, l \, \nu$ and $B \to \pi \, l \, \nu$, and $B \to D_0^* \, l \, \nu$ decays, respectively. We study such corrections with a phenomenological picture of point-like mesons (with some structure-dependent corrections), which is valid in the low-energy region of the photons and whose results we extrapolate over the complete phase space. The largest quantifiable uncertainty is due to the approximative matching to the Standard Model. In addition unknown structure-dependent contributions and model dependencies might have an impact on our findings.