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Emerging patterns of New Physics with and without Lepton Flavour Universal contributions


Algueró, Marcel; Capdevila, Bernat; Crivellin, Andreas; Descotes-Genon, Sébastien; Masjuan, Pere; Matias, Joaquim; Virto, Javier (2019). Emerging patterns of New Physics with and without Lepton Flavour Universal contributions. European Physical Journal C - Particles and Fields, 79(8):714.

Abstract

We perform a model-independent global fit to b→sℓ+ℓ− observables to confirm existing New Physics (NP) patterns (or scenarios) and to identify new ones emerging from the inclusion of the updated LHCb and Belle measurements of RK and RK∗, respectively. Our analysis, updating Refs. Capdevila et al. (J Virto JHEP 1801:093, 2018) and Algueró et al. (J Matias Phys Rev D 99(7):075017, 2019) and including these new data, suggests the presence of right-handed couplings encoded in the Wilson coefficients C9′μ and C10′μ. It also strengthens our earlier observation that a lepton flavour universality violating (LFUV) left-handed lepton coupling (CV9μ=−CV10μ), often preferred from the model building point of view, accommodates the data better if lepton-flavour universal (LFU) NP is allowed, in particular in CU9. Furthermore, this scenario with LFU NP provides a simple and model-independent connection to the b→cτν anomalies, showing a preference of ≈7σ with respect to the SM. It may also explain why fits to the whole set of b→sℓ+ℓ− data or to the subset of LFUV data exhibit stronger preferences for different NP scenarios. Finally, motivated by Z′ models with vector-like quarks, we propose four new scenarios with LFU and LFUV NP contributions that give a very good fit to data.

Abstract

We perform a model-independent global fit to b→sℓ+ℓ− observables to confirm existing New Physics (NP) patterns (or scenarios) and to identify new ones emerging from the inclusion of the updated LHCb and Belle measurements of RK and RK∗, respectively. Our analysis, updating Refs. Capdevila et al. (J Virto JHEP 1801:093, 2018) and Algueró et al. (J Matias Phys Rev D 99(7):075017, 2019) and including these new data, suggests the presence of right-handed couplings encoded in the Wilson coefficients C9′μ and C10′μ. It also strengthens our earlier observation that a lepton flavour universality violating (LFUV) left-handed lepton coupling (CV9μ=−CV10μ), often preferred from the model building point of view, accommodates the data better if lepton-flavour universal (LFU) NP is allowed, in particular in CU9. Furthermore, this scenario with LFU NP provides a simple and model-independent connection to the b→cτν anomalies, showing a preference of ≈7σ with respect to the SM. It may also explain why fits to the whole set of b→sℓ+ℓ− data or to the subset of LFUV data exhibit stronger preferences for different NP scenarios. Finally, motivated by Z′ models with vector-like quarks, we propose four new scenarios with LFU and LFUV NP contributions that give a very good fit to data.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Physics Institute
Dewey Decimal Classification:530 Physics
Scopus Subject Areas:Physical Sciences > Engineering (miscellaneous)
Physical Sciences > Physics and Astronomy (miscellaneous)
Uncontrolled Keywords:Physics and Astronomy (miscellaneous), Engineering (miscellaneous)
Language:English
Date:1 August 2019
Deposited On:12 Sep 2019 11:10
Last Modified:22 Apr 2020 21:07
Publisher:Springer
ISSN:1434-6044
OA Status:Gold
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1140/epjc/s10052-019-7216-3

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