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Article Dans Une Revue European Physical Journal C: Particles and Fields Année : 2023

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

Marcel Algueró
  • Fonction : Auteur
Aritra Biswas
  • Fonction : Auteur
Bernat Capdevila
  • Fonction : Auteur
Joaquim Matias
  • Fonction : Auteur
Martín Novoa-Brunet
  • Fonction : Auteur

Résumé

We discuss the impact of the recent LHCb update on the two lepton-flavour universality ratios $R_K$ and $R_{K^*}$, and the CMS update of $B({B_s \to \mu^+\mu^-})$ regarding the possibility of New Physics in $b\to s\ell^+\ell^-$ decays. We perform the analysis of NP scenarios through global fits of the Wilson coefficients defined in the model-independent approach of the weak effective theory holding at the $b$-quark mass. We discuss three different frameworks for this analysis: i) an update limited to the experimental data (and in particular the recent $R_{K^{(\ast)}}$ and $B({B_s \to \mu^+\mu^-})$ measurements) 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 allow 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 $R_{K^{(\ast)}}$ while the hypothesis of lepton-flavour-universal contribution to the Wilson coefficient of the semileptonic $\mathcal{O}_{9\ell}$ 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 $\mathcal{C}_{9\mu}$ Wilson coefficient are consistent throughout the different $b\to s\mu^+\mu^-$ modes and that there is no significant evidence of a non-constant $q^2$ dependencies, which would indicate the presence of a long-distance charm-loop contribution.

Dates et versions

hal-04092151 , version 1 (09-05-2023)

Identifiants

Citer

Marcel Algueró, Aritra Biswas, Bernat Capdevila, Sébastien Descotes-Genon, Joaquim Matias, et al.. To (b)e or not to (b)e: No electrons at LHCb. European Physical Journal C: Particles and Fields, 2023, 83 (7), pp.648. ⟨10.1140/epjc/s10052-023-11824-0⟩. ⟨hal-04092151⟩
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