Unitarity bounds and form-factor predictions for B-meson decays
- 1University of Cambridge
- 2Universität Bonn
Abstract
A bstract : This paper has three main aims. First, I review in a pedagogical way the unitarity bounds for form factors in B -meson decays, together with the parametrisations most commonly used in phenomenological analyses. These include BGL, BCL, CLN, and the Dispersive Matrix (DM) method. I also clarify the relation between BGL and DM, showing that they are two equivalent implementations of the same unitarity information. Second, I demonstrate that the standard BGL and DM constructions are strictly rigorous only when no subthreshold cuts are present. For B -meson decays, this requirement is fulfilled exclusively by the B → π FFs. To treat the generic case, I fully develop the GG parametrisation introduced in a previous paper and show how the same logic extends to a DM-like construction. Third, I perform three novel combined analyses of form factors and obtain predictions over the full semileptonic region. The first analysis concerns the form factors for B → π and B s → K (∗) , the second those for B → K (∗) and B s → ϕ , and the third those for B → D (∗) and Bs→ Ds(∗ ) B s → D s ∗ . All numerical results, posterior samples, analysis files, and plots are provided in the supplementary material [1].
Related
- More than a Lifetime: Towards Precision Predictions for B-Meson Decays in the Standard Model and Beyond
- Electroweak baryogenesis from charged current anomalies in B meson decays
- Light meson decays at BESIII
- Search for B meson decays to multimuon final states
- Flavorful Lepton-Number-Violating SMEFT: Loop Mixing, 0νββ and Rare Meson Decays
BibTeX
@article{gubernari2026unitarity,
title = {{Unitarity bounds and form-factor predictions for B-meson decays}},
author = {Nico Gubernari},
journal = {Journal of High Energy Physics},
year = {2026},
month = oct,
doi = {10.1007/jhep10(2026)067},
url = {https://link.springer.com/article/10.1007/JHEP10(2026)067},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Unitarity bounds and form-factor predictions for B-meson decays
AU - Nico Gubernari
PY - 2026
DA - 2026/10/07
JO - Journal of High Energy Physics
DO - 10.1007/jhep10(2026)067
UR - https://link.springer.com/article/10.1007/JHEP10(2026)067
AB - A bstract : This paper has three main aims. First, I review in a pedagogical way the unitarity bounds for form factors in B -meson decays, together with the parametrisations most commonly used in phenomenological analyses. These include BGL, BCL, CLN, and the Dispersive Matrix (DM) method. I also clarify the relation between BGL and DM, showing that they are two equivalent implementations of the same unitarity information. Second, I demonstrate that the standard BGL and DM constructions are strictly rigorous only when no subthreshold cuts are present. For B -meson decays, this requirement is fulfilled exclusively by the B → π FFs. To treat the generic case, I fully develop the GG parametrisation introduced in a previous paper and show how the same logic extends to a DM-like construction. Third, I perform three novel combined analyses of form factors and obtain predictions over the full semileptonic region. The first analysis concerns the form factors for B → π and B s → K (∗) , the second those for B → K (∗) and B s → ϕ , and the third those for B → D (∗) and B_s→ D_s^(∗ ) B s → D s ∗ . All numerical results, posterior samples, analysis files, and plots are provided in the supplementary material [1].
SN - 1029-8479
ER -