# Searching for New Physics with $b\to s\tau^+\tau^-$ processes

Abstract : In recent years, intriguing hints for the violation of lepton flavor universality (LFU) have been accumulated in semileptonic B decays, both in the charged-current transitions b→cℓ-ν¯ℓ (i.e., RD, RD*, and RJ/ψ) and the neutral-current transitions b→sℓ+ℓ- (i.e., RK and RK*). Hints for LFU violation in RD(*) and RJ/ψ point at large deviations from the standard model (SM) in processes involving tau leptons. Moreover, LHCb has reported deviations from the SM expectations in b→sμ+μ- processes as well as in the ratios RK and RK*, which together point at new physics (NP) affecting muons with a high significance. These hints for NP suggest the possibility of huge LFU-violating effects in b→sτ+τ- transitions. In this Letter, we predict the branching ratios of B→Kτ+τ-, B→K*τ+τ-, and Bs→ϕτ+τ-, taking into account NP effects in the Wilson coefficients C9(′)ττ and C10(′)ττ. Assuming a common NP explanation of RD, RD(*), and RJ/ψ, we show that a very large enhancement of b→sτ+τ- processes, of around 3 orders of magnitude compared to the SM, can be expected under fairly general assumptions. We find that the branching ratios of Bs→τ+τ-, Bs→ϕτ+τ-, and B→K(*)τ+τ- under these assumptions are in the observable range for LHCb and Belle II.
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https://hal.archives-ouvertes.fr/hal-01792822
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Submitted on : Tuesday, May 15, 2018 - 7:00:38 PM
Last modification on : Wednesday, November 3, 2021 - 7:55:42 AM

### Citation

Bernat Capdevila, Andreas Crivellin, Sébastien Descotes-Genon, Lars Hofer, Joaquim Matias. Searching for New Physics with $b\to s\tau^+\tau^-$ processes. Physical Review Letters, American Physical Society, 2018, 120 (18), pp.181802. ⟨10.1103/PhysRevLett.120.181802⟩. ⟨hal-01792822⟩

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