$|V_{cb}|$ determinations from $\bar{B} \to D^{(*)} \ell \barν$ decays within the SM and beyond
Year: 2026
Type: preprint
Abstract: We investigate the $|V_{cb}|$ determinations from exclusive semi-leptonic $\bar{B} \to D^{(*)}\ell\barν$ decays, together with comprehensive Bayesian fit analyses of the $\bar{B} \to D^{(*)}$ transition form-factors, by taking into account recent updates of experimental distribution data and theoretical evaluations. Several commonly adopted form-factor parameterizations, including BSZ, BGL and HQET, have been considered under different fit scenarios. We compare the fitted values and study how the $|V_{cb}|$ determinations depend on the form-factor parameterizations and on the treatment of the experimental inputs. Following the fit setup adopted by the PDG, we find that the BSZ, BGL, and HQET results are mutually consistent at specific truncation orders of the form-factor parameterizations. Our representative determinations are $|V_{cb}|=(39.3\pm0.3)\times10^{-3}$ for BGL $(N_F=2)$ and $(39.5\pm0.3)\times10^{-3}$ for HQET $(3/2/1)$, compatible with the official PDG average. We also consider new-physics effects that can contribute to $\bar{B} \to D^{(*)}\ell\barν$. The allowed regions remain compatible with vanishing new-physics Wilson coefficients at the $95\%$ confidence level, and the improvements in agreement with the data are modest. The exclusive-inclusive $|V_{cb}|$ puzzle remains unresolved in the present analysis.
Source: arXiv (Cornell University)
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G2428087542, Development of the Energy Frontier and International Human Resources toward Unified Understanding of Interaction, Exploring frontier of particle physics with precise prediction of flavor physics, B中間子崩壊から解き明かす新物理のフレーバー構造, G6325165843, Exploration of the particle physics frontier at the Super B-factory and cultivation o f young researchers
OpenAlex ID: W7165017371