Related papers: Lepton Universality, Rare Decays and Split Fermion…
We construct an expression for a general lepton flavour universality (LFU) ratio, $R_{X}$, in $b\to s l^+ l^-$ decays in terms of a series of hadronic quantities which can be treated as nuisance parameters. This expression allows to include…
A soft-wall warped extra dimension allows one to relax the tight constraints imposed by electroweak data in conventional Randall-Sundrum models. We investigate a setup, where the lepton flavour structure of the Standard Model is realised by…
Motivated by the measurements of $b\to s\ell^+\ell^-$ transitions, including $R(K)$ and $R(K^*)$, we examine lepton flavour (universality) violation in $B$ decays and its connections to $\mu\to e\gamma$ in generic leptoquark models.…
Motivated by renewed evidence for new physics in $b \to s\ell\ell$ transitions in the form of LHCb's new measurements of theoretically clean lepton-universality ratios and the purely leptonic $B_s\to\mu^+\mu^-$ decay, we quantify the…
We calculate the predictions for lepton flavour violating (LFV) tau and muon decays, $l_j \to l_i \gamma$, $l_j \to 3 l_i$, $\mu-e$ conversion in nuclei and LFV semileptonic tau decays $\tau \to \mu PP$ with $PP= \pi^+\pi^-, \pi^0\pi^0,…
General expressions for one-loop contributions associated with lepton-flavor violating decays of the standard model-like Higgs boson $h\to e_b^\pm e_a^\mp$ and gauge boson $Z\to e^\pm_b e_a^\mp$ are introduced in the unitary gauge. The…
We consider the minimal 3-3-1 model with three sterile neutrinos transforming as singlet under the $SU(3)_L\otimes U(1)_X$ symmetry. This model, with or without sterile neutrinos, predicts flavor violating interactions in both quark and…
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 $\tau^+ \tau^-$…
We study the one-loop supersymmetric contributions to lepton-flavor violating $Z$ -boson decays in a fully left-right symmetric model. In addition to right-handed scalar neutrinos, the decays could receive important contributions from…
We study the branching ratios of the lepton flavor violating processes \mu -> e\gamma, \tau -> e\gamma and \tau -> \mu\gamma in the split fermion scenario, with the assumption that the new Higgs doublet is restricted to the 4D brane (thin…
We investigate the effect of scalar leptoquarks and family non-universal $Z^\prime$ boson on the rare leptonic decays of $B_{s, d}^*$ mesons, mediated by the FCNC transitions $b \to (d, s) l^+ l^-$. They are sensitive to a variety of new…
It has been recently proposed that neutrino mass could originate from Yukawa interactions of leptons with new colored particles. This raises the interesting possibility of testing mass generation through copious production of those…
A general relationship is formulated between the contributions of `Weak Annihilation' (WA) to inclusive semileptonic decays of heavy flavour hadrons and the matrix elements of four fermion operators. We argue that nonperturbative…
In a recent paper, we showed that tree level up-down unification of fermion Yukawa couplings is a natural consequence of a large class of supersymmetric models. They can lead to viable quark masses and mixings for moderately large values of…
We consider a flavoured $B-L$ gauge symmetry under which only the third generation fermions are charged. Such a symmetry can survive at low energies (~TeV) while still allowing for two superheavy right-handed neutrinos, consistent with…
A measurement of the ratio of the branching fractions, $R_{\tau/e} = B(W \to \tau \nu)/ B(W \to e \nu)$, is performed using a sample of $W$ bosons originating from top-quark decays to final states containing $\tau$-leptons or electrons.…
We study the recently found anomalies in $B$-meson decays within a scenario with a warped extra dimension where the Standard Model fermions are propagating in the bulk. The anomalies are then interpreted as the result of the exchange of…
We study supersymmetric models with a GUT-sized extra dimension, where both the Higgs fields and the SUSY breaking hidden sector are localized on a 4D brane. Exponential wave function profiles of the matter fields give rise to hierarchical…
Lepton flavor universality can be tested in the semileptonic decays $\Lambda_b\to \Lambda_c^{(\ast)}$ where $\Lambda_c^{(\ast)}$ denotes either the ground state $\Lambda_c(2286)$ (with $J^P=1/2^+$) or its orbital excitations…
The pseudo-Goldstone boson mechanism for the ``doublet-triplet splitting'' problem of the grand unified theory can be naturally implemented in the scenario with extra dimensions and branes. The two SU(6) global symmetries of the Higgs…