Model-independent investigation of rare semileptonic b→ulν¯l decay processes

Abstract

Motivated by the recent observation of lepton universality violation in the flavour changing charged current transitions b → clν l , we intend to scrutinize the lepton non-universality effects in rare semileptonic B meson decays involving the quark level transitions b → ulν l . In this regard, we envisage the model-independent approach and consider the generalized effective Lagrangian in the presence of new physics and constrain the new parameters by using the experimental branching fractions of B + u → l + ν l and B − → π 0 µ −ν µ processes, where l = e, µ, τ . We then estimate the branching ratios and forward-backward asymmetries of B (s) → P (V )lν l processes, where P (= K, π, η ( ) ) denotes the pseudoscalar meson and V (= K * , ρ) is the vector meson. We also find out various lepton non-universality parameters in these processes in the presence of new physics.

Impact of vector new physics couplings on $B_s \to (K,\,K^{\ast})τν$ and $B \to πτν$ decays

“…Very recently, in Ref. [91], the authors have performed a model independent analysis of NP effects in B s → (K, K * )τ ν decays using the experimental constraints coming from B → τ ν channel. Our main aim is to study the implication of R D , R D * , R J/Ψ , and R l π anomalies in B s → (K, K * )τ ν and B → πτ ν semileptonic decays in a model dependent way.…”

Probing new physics with B¯→ρ(770)ℓ−

“…The deviations are correlated when the new operators are included in the effective Hamiltonian and, as shown in Fig.16, large effects are possible in corners of the parameter space of the new effective couplings. Concerning R π in SM, the value R π = 0.641(17) is obtained using lattice form factors at large q 2 [67], the range [0.654, 0.764] is found in [68], R π = 0.7 together with R ρ 0.573 is found using form factors computed in pQCD [69], R π 0.731 and R ρ 0.585 are quoted in [70]. The effect of a new charged Higgs reduces the SM result for R π and R ρ [71].…”

“…The effect of a new charged Higgs reduces the SM result for R π and R ρ [71]. Considering a single NP operator per time, values for R π up to 4 are obtained in [68], the range [0.5, 1.38] is found in [69], while the inclusion only of the pseudoscalar and scalar operators in the effective Hamiltonian gives R π ∈ [0.5, 1.2] [49]. 5 Remarks about the modeB → a 1 (1260) −ν As forB → ρ(ππ) −ν , the channelB → a 1 (ρπ) −ν can be numerically analyzed in SM and in the NP extension Eq.…”

Impact of vector new physics couplings on Bs→(K,K*)τνRajeev1, Dutta2 2018Phys. Rev. D14030View full textAdd to dashboardCite

“…Very recently, in Ref. [97], the authors have performed a model-independent analysis of NP effects in B s → ðK; K Ã Þτν decays using the experimental constraints coming from the B → τν channel. Similarly, in Ref.…”

“…This is where we differ significantly from Refs. [97,98]. Again, for various meson to meson transition form factors, we use very recent lattice QCD results of Refs.…”