Related papers: Tau lepton Michel parameters and new physics
In a recent paper, 8 semileptonic parameters were defined to specify the most general Lorentz-invariant spin correlation functions for 2-body tau decays. These parameters can be used to search for anomalous longitudinal-versus transverse…
Theoretical and experimental situation in physics of heavy neutrinos $(M_N>M_Z)$ is briefly presented. Various experimental bounds on heavy neutrino masses and mixings are shortly reviewed. Special attention is paid to possibility of…
We review many of the contributions of the CLEO experiment to tau physics. Topics discussed are: branching fractions for major decay modes and tests of lepton universality; rare decays; forbidden decays; Michel parameters and spin physics;…
$\tau$ is playing an important role in the current B-physics indications from experiments of lepton flavor universality violations(LFUV). This suggests it be given increasing attention theoretically in the coming years, given also the fact…
The measurements of the mean lifetime of the tau lepton are reviewed. The conditions for measuring the lifetime at various e+e- colliders are compared and the analysis methods are briefly described. The new developments since the previous…
The status of several precisely measured electroweak parameters is reviewed. Natural relations among them are shown to constrain the Higgs mass, m_H, as well as various ``New Physics'' effects. Indications of an anomalous Zb anti-b coupling…
Several models of neutrino masses predict the existence of neutral heavy leptons. Here, we review current constraints on heavy neutrinos and apply a new formalism separating new physics from Standard Model. We discuss also the indirect…
We propose two different and complementary observables for singling out possible signals of physics beyond the standard model in the semi-leptonic decays $\Lambda_b \to \Lambda_c \ell{\bar \nu}_{\ell}$, both with the $\tau$ lepton and with…
We consider a spin-0 unparticle and calculate its contribution to the weak properties of a fermion, which in the proper limit reduce to previously reported results for the electromagnetic properties. We then obtain an estimate for the…
We speculate about the possible interpretations of the recently observed excess in the $h \to \tau \mu$ decay. We derive a robust lower bound on the Higgs boson coupling strength to a tau and a muon, even in presence of the most general new…
Bayesian, classical, and extended maximum likelihood approaches to estimation of upper limits in experiments with small numbers of signal events are surveyed. The discussion covers only experiments whose outcomes are well described by a…
The nucleon elastic form factors are generally interpreted as a mapping of the charge and magnetic current distributions of the proton and neutron. New high Q^2 measurements have opened up fundamental questions about G_ep that remain to be…
We discuss the potential of long-baseline neutrino oscillation experiments to determine deviations from maximal \nu_\mu-\nu_\tau mixing. We compare the obtainable sensitivities to predictions from neutrino mass models and to the size of…
This article reviews and updates the Standard Model prediction of the tau lepton g-2. Updated QED and electroweak contributions are presented, together with new values of the leading-order hadronic term, based on the recent low energy e+ e-…
The status of the new standard model is briefly surveyed, with emphasis on experimental tests, unique features, theoretical problems, necessary extensions, and possible TeV signatures of Planck scale physics.
While electron and muon dipole moments are well-established precision probes of physics beyond the standard model, it is notoriously challenging to test realistic new-physics (NP) scenarios for the $\tau$ lepton. Constructing suitable…
From the analytic oscillation probability for high energy atmospheric neutrinos in the presence of new physics in propagation, it is argued that the components $|\epsilon_{e\mu}|$ and $|\epsilon_{\mu\tau}|$ as well as the quantity…
In this talk I review the present bounds on the tau neutrino, concentrating on the possibility of bringing the mass bound below an MeV.
The leptonic decays of the tau lepton provide relevant tests on the structure of the weak currents and the universality of their couplings to the gauge bosons. The hadronic tau decay modes constitute an ideal tool for studying low--energy…
This is a review of new results on the Tau lepton. The lifetime has been measured with improved precision, allowing the test of lepton universality to 0.2% level. There are several new measurements of the branching ratios for the hadronic…