Related papers: Revisiting Lepton Flavour Universality in B Decays
We explore a scenario of New Physics entering the description of $B\to K^{(\ast )} \mu \mu$ decay through couplings to the operators ${\cal O}_{9,10}^\prime$, satisfying $C_9^\prime = - C_{10}^\prime$. From the current data on ${\cal…
Among (semi)leptonic rare $B$-decays induced by the $b \to d$ flavor changing neutral current, the decay $B^+ \to \pi^+ \mu^+ \mu^-$ is the only one observed so far experimentally. Related decays involving the $e^+e^-$ and $\tau^+ \tau^-$…
New neutral heavy gauge bosons ($Z^\prime$) are predicted within many extensions of the Standard Model. While in case they couple to quarks the LHC bounds are very stringent, leptophilic $Z^\prime$ bosons (even with sizable couplings) can…
The flavor changing decays of heavy bottom quarks to the corresponding lighter quarks ($u$, $c$ and $s$) in various $B$-meson decays via charged current and neutral current semileptonic transitions have emerged as promising candidates to…
We study the impact of minimal non-supersymmetric models of resonant leptogenesis on charged lepton flavour violation and the neutrino mixing angle theta(13). Possible low-scale flavour realisations of resonant tau-, mu- and e-leptogenesis…
The branching fraction $\mathcal{B}(B^0 \to D^{*-}\tau^+\nu_{\tau})$ is measured relative to that of the normalization mode $B^0 \to D^{*-}\pi^+\pi^-\pi^+$ using hadronic $\tau^+ \to \pi^+\pi^-\pi^+(\pi^0)\overline{\nu}_{\tau}$ decays in…
Ratios of branching fractions of semileptonic B decays, $(B \to H \mu \mu)$ over $(B \to H ee)$ with $H=K, K^*,X_s, K_0(1430), \phi, \ldots$ are sensitive probes of lepton universality. In the Standard Model, the underlying flavor changing…
Taking advantage of the fact that the flavor of the neutrino in semileptonic $B$ decays $B\to D^{(*)}\tau\nu$ is not known, we show how a minimal set of higher-dimensional lepton flavor violating (LFV) operators can explain the $R(D^{(*)})$…
Inspired by the recent hints of lepton flavor universality violation in $b\to s\ell\ell$ and $b\to c\ell\nu$ transitions, we study lepton flavor violating exclusive $\Lambda_b\to\Lambda\ell_1^+\ell_2^-$ ($\ell_1\neq \ell_2$) decay, which is…
The recent measurements of lepton flavor university (LFU) violating observables in semileptonic $b \to c \ell \bar{\nu} $ and $b\to s\ell^+ \ell^-$ transitions by various experiments exhibit $(2-3)\sigma$ deviations from their corresponding…
Recent measurements have revealed a number of intriguing deviations from the Standard Model predictions in $B$ meson decays, in particular in observables testing lepton flavour universality. We review their experimental status and…
We organise the four-fermion vector current interactions below the weak scale -- i.e., in the low energy effective field theory (LEFT) -- into irreps of definite parity and $SU(N)$ flavour symmetry. Their coefficients are thus arranged into…
The semileptonic decays $\tau^- \to \mu^- M (M=\pi^0,\eta,\eta')$ could be sensitive probe for new physics scenarios with lepton flavor violation(LFV). Motivated by the recent Belle measurement, we investigate these decays in type III…
We investigate Lepton-Flavor Violating (LFV) decays of Higgs to muon-tau in the supersymmetric economical 3-3-1 (SUSYE331) model. In the presence of flavor mixing in sleptons {mu,tau} and large values of v/v', the ratio of Br(H…
When lepton flavour effects in thermal leptogenesis are active, they introduce important differences with respect to the case in which they are neglected, the so-called one-flavour approximation. We investigate analytically and numerically…
The LHCb Collaboration's measurement of R_K = B(B+ -> K+ mu+ mu-)/B(B+ -> K+ e+e-) lies 2.6 sigma below the Standard Model prediction. Several groups suggest this deficit to result from new lepton non-universal interactions of muons. But…
In recent times, several hints of lepton non-universality have been observed in semileptonic $B$ meson decays, both in the charged-current ($b \to c l \bar \nu_l$) and neutral-current ($b \to s ll $) transitions. Motivated by these…
Many models for physics beyond the Standard Model predict lepton-flavour violating decays of charged leptons at a level which may become observable very soon. In the present paper we investigate the decays of a Tau into three charged…
We propose a novel method to probe the persistent hints of Lepton Flavour Universality violation observed in semileptonic $B$ decays. Relying on the specific properties of the Belle II experiment, it consists in comparing the inclusive…
The deviations with respect to the Standard Model (SM) that are currently observed in $b \to s \ell\ell$ transitions (the so-called flavour anomalies) can be interpreted in terms of different New Physics (NP) scenarios within a…