https://doi.org/10.1140/epjc/s10052-023-11191-w
Regular Article - Theoretical Physics
Charming penguins and lepton universality violation in
decays
1
INFN Sezione di Roma Tre, Via della Vasca Navale 84, 00146, Rome, Italy
2
Institut für Theoretische Teilchenphysik, Karlsruhe Institute of Technology, 76131, Karlsruhe, Germany
3
INFN Sezione di Roma, Piazzale Aldo Moro 2, 00185, Rome, Italy
4
Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
5
Institut für Physik, Humboldt-Universität zu Berlin, 12489, Berlin, Germany
6
C.N. Yang Institute for Theoretical Physics, Stony Brook University, 11794, Stony Brook, NY, USA
Received:
14
April
2022
Accepted:
3
January
2023
Published online:
24
January
2023
The LHCb experiment has recently presented new results on Lepton Universality Violation (LUV) in decays involving
in the final state, which strengthen the recent evidence of LUV obtained in
decays and the previous measurements of
. While LUV observables in the Standard Model are theoretically clean, their predictions in New Physics scenarios are sensitive to the details of the hadronic dynamics, and in particular of the charming penguin contribution. In this work, we show how a conservative treatment of hadronic uncertainties is crucial not only to assess the significance of deviations from the Standard Model but also to obtain a conservative picture of the New Physics responsible for LUV. Adopting a very general parameterization of charming penguins, we find that: (i) current data hint at a sizable
and helicity dependence of charm loop amplitudes; (ii) conservative NP solutions to B anomalies favour a left-handed or an axial lepton coupling rather than a vector one.
© The Author(s) 2023
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