Investigating the potential of [formula omitted] to probe lepton flavor universality violation

Abstract

In this work we study the potential of the lepton flavor ratios RKτμ≡Γ(B→Kτ+τ−)/Γ(B→Kμ+μ−) and RK⁎τμ≡Γ(B→K⁎τ+τ−)/Γ(B→K⁎μ+μ−) to probe lepton flavor universality (LFU) violation in τ−μ sector. We show that these ratios can deviate from their SM values even if the new physics couplings are universal in nature, i.e., having equal couplings to e, μ and τ leptons. Therefore in order to utilize these observables to probe LFU violation, we need to compare the allowed range of RK(⁎)τμ for class of solutions with only universal couplings to leptons and solutions having both universal and non-universal components. For the current b→sℓℓ (ℓ=e,μ) data, we find that these two class of solutions can be discriminated provided the measured value of RK⁎τμ is greater than the SM prediction.