Related papers: Three generations mixing and the $\tau$ decay puzz…
LHC searches with $\tau$ leptons in the final state are always inclusive in missing-energy sources. A signal in the flavor-violating Higgs decay search, $h\to\tau\mu$, could therefore equally well be due to a flavor conserving decay, but…
The evaluation, systematic analysis and numerical study of the semileptonic $\tau$-lepton decays with two mesons in the final state has been made in the frame of the standard model extended by right handed neutrinos. In the analysis,…
The \tau -> (\omega, \phi)P^-\nu decays, where P^-=\pi^-, K^-, are considered within a phenomenological model with dominance of meson intermediate states. We assume SU(3) flavor symmetry to fix some of the unknown strong interaction…
The existence of large \nu_\mu-\nu_\tau mixing suggests the likelihood of large smuon-stau mixing in supersymmetric models, leading to \mu and \tau number violation. In addition to interesting signatures in slepton and neutralino production…
We have derived constraints on the tau neutrino mass and fourth generation mixing from an analysis of the partial widths of tau lepton decays, in particular: tau -> e nu nu_tau, tau -> mu nu nu_tau, tau -> pi nu_tau, tau -> K nu_tau. We…
The $\tau$ lepton arising from the scalar tau ($\st$) decay is naturally polarized. $\ptau$ depends on the left--right mixing of the $\st$ and the gaugino--higgsino mixing of the neutralino. The polarization $\ptau$ could be measured from…
We evaluate the compositeness effects of tau lepton on the vertex W-tau-nu(tau) in the context of an effective Lagrangian approach. We consider that only the third family is composed and we get the corrections to the non universal lepton…
Fermion masses and mixing, both in the quark and leptonic sector, are discussed within the approach to the Yukawa puzzle proposed by Arkani-Hamed and Schmaltz. In the quark sector we have shown that at least two extra dimensions are…
Model independent tests for symmetry violations in tau decays are important for determining whether the tau lepton is elementary or, instead, macroscopic. Such tests are also significant steps towards resolving the outstanding "e - mu -…
Lepton generation universality holds very well in Z decays, but appears to be violated in recent LEP data of W leptonic decay branching fractions. If this trend persists, a consistent and natural explanation is a model of generation…
We show that the large mixing between $\nu_\mu$ and $\nu_\tau$ observed by the SuperKamiokande collaboration is a quite natural prediction in a large class of seesaw models. This large mixing is basically due to the unparallel family…
Within the type-I seesaw framework with three heavy right chiral neutrinos and in the basis where the latter and the charged leptons are mass diagonal, a near `mu-tau' symmetry in the neutrino sector is strongly suggested by the neutrino…
The study of $B \to \tau^+ \tau^- (X)$ decays can provide us with a better understanding of the third generation, and can be a useful probe of physics beyond the standard model. We present a model independent analysis of these decays. We…
We propose that leptonic CP violation arises from a breaking of the mu-tau exchange symmetry in the neutrino mass matrix which in turn is indicated by the near maximal atmospheric neutrino mixing and the near zero \theta_{13}. We find that…
We discuss a possibility to explain the excess of $h\to\mu\tau$ at one-loop level. We introduce three generation of vector-like lepton doublet $L'$ and two singlet scalars $S_{1,2}$ which are odd under $Z_2$, while all the standard model…
We explore the possibility of a fourth generation in the gauge-coupling-unified, minimal supersymmetric (MSSM) framework. We find that a sequential fourth generation (with a heavy neutrino $\nu'$) can still fit, surviving all present…
In this paper, we generally analyze the $\mu - \tau$ reflection symmetry modified by small mixings of charged leptons and how will future experiments verify deviations from the predictions of the symmetry. As an approximation, the…
Models of neutrino masses are discussed capable of explaining in a natural way the maximal mixing between $\nu_{\mu}$ and $\nu_{\tau}$ observed by the Super-Kamiokande collaboration. For three generations of leptons two classes of such…
The recent measurements of the Michel parameters in tau decays enable, for the first time, a thorough analysis of the leptonic sector. In general, in models beyond the Standard Model, these parameters will be altered through changes in the…
We study the consequences of the $Z_2$-symmetry behind the $\mu$--$\tau$ universality in neutrino mass matrix. We then implement this symmetry in the type-I seesaw mechanism and show how it can accommodate all sorts of lepton mass…