PoS - Proceedings of Science
Volume 414 - 41st International Conference on High Energy physics (ICHEP2022) - Quark and Lepton Flavour Physics
Modified HQET power counting for constrained second-order power corrections in $B \to D^{(*)}l\nu$: $R(D^{(*)})$, $|V_{cb}|$ and New Physics
F.U. Bernlochner, Z. Ligeti, M. Papucci, M.T. Prim*, D.J. Robinson and C. Xiong
Full text: pdf
Pre-published on: December 06, 2022
Published on: June 15, 2023
Abstract
We develop a modified power-counting within the heavy quark effective theory (HQET),
that results in a highly constrained set of second-order power corrections in the heavy quark expansion, compared to the standard approach. We implement this modified expansion to determine all $\bar{B} \to D^{(*)}$form factors, both within and beyond the Standard Model, to $\mathcal{O}(\alpha_s, \alpha_s/m_{c,b}, 1/m_{c,b}^2)$. Using measured $\bar{B} \to D^{(*)}\ell \bar{\nu}$ differential branching fractions for light leptons ($\ell = e, \mu$), we constrain not only leading and subleading Isgur-Wise functions, but also the $1/m_{c,b}^2$ corrections from subsubleading terms. We provide updated precision predictions for $\bar{B} \to D^{(*)}\tau \bar{\nu}$ decay rates, lepton universality ratios, and the CKM matrix element $|V_{cb}|$.
DOI: https://doi.org/10.22323/1.414.0758
How to cite

Metadata are provided both in "article" format (very similar to INSPIRE) as this helps creating very compact bibliographies which can be beneficial to authors and readers, and in "proceeding" format which is more detailed and complete.

Open Access
Creative Commons LicenseCopyright owned by the author(s) under the term of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.