https://doi.org/10.1140/epjc/s10052-025-14598-9
Regular Article - Theoretical Physics
semileptonic sum rule: extension to angular observables
1
KEK Theory Center, IPNS, KEK, 305-0801, Tsukuba, Japan
2
Graduate Institute for Advanced Studies, SOKENDAI, 305-0801, Tsukuba, Ibaraki, Japan
3
Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, 464-8602, Nagoya, Japan
4
Institute for Advanced Research, Nagoya University, 464-8601, Nagoya, Japan
5
Institute for Theoretical Particle Physics (TTP), Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Str. 1, 76131, Karlsruhe, Germany
6
Department of Liberal Arts, Saitama Medical University, 350-0495, Moroyama, Saitama, Japan
7
Institute of Particle Physics and Key Laboratory of Quark and Lepton Physics (MOE), Central China Normal University, 430079, Wuhan, Hubei, China
a
iguro@eken.phys.nagoya-u.ac.jp
Received:
30
June
2025
Accepted:
29
July
2025
Published online:
9
September
2025
Lepton flavor universality is a key prediction of the Standard Model of particle physics, and any violation of it immediately indicates the existence of new physics. Given the recent discrepancy of more than 
in charged current semileptonic B meson decays and the absence of evident signals at the Large Hadron Collider, independent cross-checks become invaluable. In this context, semileptonic sum rules based on heavy quark symmetry are interesting, since they allow us to check the consistency of experimental results. In this paper, we report newly found sum rules among angular observables of mesonic and baryonic 
decays holding exactly in the large mass limit of heavy quarks. Moreover, we investigate corrections to the sum rule in realistic situations and discuss phenomenological implications.
The original online version of this article was revised: In Table 1, two entries in the “Value” column were incorrect. Value 1 has been corrected from 0.182 to 0.18, and Value 5 from 0.02 ± 0.183i to 0.18.
An erratum to this article is available online at https://doi.org/10.1140/epjc/s10052-025-14757-y.
© The Author(s) 2025
corrected publication 2025
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Funded by SCOAP3.
