Published 2023 | Version v1
Journal article

To (b)e or not to (b)e. No electrons at LHCb

  • 1. Institut de Física d'Altes Energies (IFAE), The Barcelona Institute of Science and Technology, Campus UAB, 08193, Bellaterra (Barcelona) (Spain)
  • 2. Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona (Spain)
  • 3. DAMTP, University of Cambridge, Wilberforce Road, CB3 0WA, Cambridge (United Kingdom)
  • 4. Université Paris-Saclay, CNRS/IN2P3, IJCLab, 91405, Orsay (France)
  • 5. Istituto Nazionale di Fisica Nucleare, Sezione di Bari, Via Orabona 4, 70126, Bari (Italy)

Description

We discuss the impact of the recent LHCb update on the two lepton-flavour universality ratios RK and RK, and the CMS update of B(Bs → µ+µ) regarding the possibility of New Physics in b → s+ decays. We perform global fits of the New Physics Wilson coefficients defined in the model-independent approach of the Weak Effective Theory at the b-quark mass. We discuss three different frameworks for this analysis: (i) an update limited to the experimental data but using the same theoretical framework as in earlier works, (ii) a full update concerning both the experimental inputs and the theoretical framework, (iii) an analysis without the LHCb results on electron modes. The comparison between these various sets of results allows us to identify the differences stemming from the various components of the analysis: new experimental results, new inputs for the hadronic form factors, the role played by LHCb data on electron modes. As expected, the significance of all New Physics hypotheses gets reduced after the LHCb announcements on RK() while the hypothesis of a lepton-flavour-universal contribution to the Wilson coefficient of the semileptonic O9 operators (possibly with a very small lepton-flavour-universality violating component) is clearly reinforced. We also discuss the possibility of a long-distance charm-loop contribution through a mode-by-mode analysis and we find that the preferred values for the C9μ Wilson coefficient are consistent throughout the different b → sµ+µ modes and that there is no significant evidence of non-constant q2 dependencies, which would indicate the presence of a long-distance charm-loop contribution beyond those already included.

Availability note (English)

Available from: http://dx.doi.org/10.1140/epjc/s10052-023-11824-0

Additional details

Publishing Information

Journal Title
European Physical Journal. C, Particles and Fields (Online)
Journal Volume
83
Journal Issue
7
Journal Page Range
vp.
ISSN
1434-6052
CODEN
EPCFFB

Optional Information

Notes
AID: 648