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Semileptonic baryon decays $Ξ_{b} \to Ξ_{c} ℓ^{-} {\bar{ν}}_{ℓ}$ in perturbative QCD

Zhou Rui ^1,*, Zhi-Tian Zou^1,†, Ya Li ^2,‡, and Ying Li ^1,§

¹Department of Physics, Yantai University, Yantai 264005, China
²Department of Physics, College of Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China

^*Contact author: jindui1127@126.com
^†Contact author: zouzt@ytu.edu.cn
^‡Contact author: liyakelly@163.com
^§Contact author: liying@ytu.edu.cn

Phys. Rev. D 111, 113006 – Published 20 June, 2025

DOI: https://doi.org/10.1103/qncx-7j7b

Abstract

We perform a detailed analysis of the semileptonic $Ξ_{b} \to Ξ_{c} ℓ^{-} {\bar{ν}}_{ℓ}$ decays within the perturbative QCD framework. In our study, the $Ξ_{b} \to Ξ_{c}$ transition form factors are calculated using several popular models for baryonic light-cone distribution amplitudes. These form factors are then employed to analyze a range of observable quantities for the semileptonic processes via the helicity formalism. Our work presents predictions for the branching fractions of these decays for both the $τ$ and $e$ channels. Notably, the obtained lepton flavor universality ratio, $R_{Ξ_{c}} \approx 0.3$ , may offer new insights into the $R^{(*)}$ puzzle. Furthermore, we investigate various angular observables, such as forward-backward asymmetries, lepton-side convexity parameters, and polarization asymmetries, which provide complementary information regarding potential new physics in $b$ -baryonic semileptonic transitions. The numerical results for these angular observables are presented as both functions of $q^{2}$ and as averaged values. We observe that the lepton mass plays a significant role in shaping the angular distributions, affecting most of the observables under consideration. These results are expected to be valuable for both current and future experimental investigations of semileptonic heavy-to-heavy baryon decays.

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References (97)

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Phys. Rev. D 111, 113006– Published 20 June, 2025

Vol. 111, Iss. 11 — 1 June 2025

Received 4 April 2025
Accepted 3 June 2025

DOI: https://doi.org/10.1103/qncx-7j7b

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

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Semileptonic baryon decays $Ξ_{b} \to Ξ_{c} ℓ^{-} {\bar{ν}}_{ℓ}$ in perturbative QCD

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Semileptonic baryon decays Ξb→Ξcℓ−ν¯ℓ in perturbative QCD

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Semileptonic baryon decays $Ξ_{b} \to Ξ_{c} ℓ^{-} {\bar{ν}}_{ℓ}$ in perturbative QCD