Related papers: Lepton Universality, |V_{us}| and search for secon…
We present the preliminary results from the search of the non-conservation of lepton flavor number in the decay of a $\tau$ to a lighter mass lepton and a pseudo-scalar meson, performed using $e^+e^- \to \tau^+\tau^-$ events collected at a…
The branching ratio for the decay tau->e nue nutau has been measured using Z0 decay data collected by the OPAL experiment at LEP. In total 33073 tau->e nue nutau candidates were identified from a sample of 186197 selected tau decays, giving…
We present a search for the decay $B^{-} \to \tau^{-} \bar{\nu}_{\tau}$ in a sample of $88.9 \times 10^{6}$ $B\bar{B}$ pairs recorded with the BaBar detector at the SLAC $B$-Factory. One of the two $B$ mesons from the $\Upsilon(4S)$ is…
A search for the lepton flavour violating decay tau -> mu gamma has been performed using 221.4/fb of data collected at an e+e- centre-of-mass energy of 10.58 GeV with the BABAR detector at the PEP-II storage ring. The search has an…
One of the key assumptions of the Standard Model of fundamental particles is that the interactions of the charged leptons, namely electrons, muons, and taus, differ only because of their different masses. While precision tests comparing…
Using data collected with the CLEO-III detector at the CESR e+e- collider, we report on a first observation of the decay of the Upsilon(3S) to tau tau, and precisely measure the ratio of branching fractions of Upsilon(nS),n=1,2,3 to tau tau…
The leptonic $\tau$ decays are calculated at the 1-loop level in the Minimal Supersymmetric Standard Model. The deviation from the $\tau - \mu - e$ universality is studied as a function of the supersymmetric parameters and discussed in the…
Since 1999, the B-factories collaborations BABAR and Belle have accumulated and studied large samples of tau lepton pairs. The experimental results on Lepton Universality checks and Lepton Flavour Violation searches are reported.
The reconstruction of tau-pair production, $e^{+}e^{-} \to \tau^{+}\tau^{-}$, from the subsequent 3-prong ($\tau^{+} \rightarrow \pi^{+} \pi^{-} \pi^{+} \bar{\nu}_{\tau}$) and 1-prong ($\tau^{-} \to \ell^{-} \bar{\nu}_{\ell} \nu_{\tau}$,…
Analytic expressions are given for the $\tau$ decays into three charged leptons, $\tau\rta \ell\ell\overline \ell\nu_\tau\overline \nu_\ell$, where the $\ell$ are combinations of electrons and muons, and for the radiative decays $\tau\rta…
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…
Searches for lepton-flavor-violating decay of a tau lepton to a lighter mass lepton and a photon have been performed with the entire dataset of (963 +- 7) x 10^6 tau decays collected by the BaBar detector near the Upsilon(4S), Upsilon(3S)…
Hints of lepton flavor universality violation observed in various flavor ratios such as $R_D$, $R_{D^*}$, $R_{J/\psi}$, $P_\tau^{D^*}$ and $F_L^{D^*}$ in $B\to D^{(*)}\,\ell \, \nu$ and $B_c\to J/\psi \, \ell\, \nu$ charge current decays…
Charged-lepton-flavor-violation is predicted in several new physics scenarios. We update the analysis of $\tau$ lepton decays into a light charged lepton ($\ell$ = $e^{\pm}$ or $\mu^{\pm}$) and a vector meson ($V^0$ = $\rho^0$, $\phi$,…
The present experimental status of searches for lepton flavor violating decays of the $\tau$ lepton to a lighter mass lepton and a photon or a pseudoscalar meson is presented. The results obtained are from $e^+e^-$ annihilation data…
The \tau \to (a_1 h)^- \nu_{\tau} decays of the \tau-lepton are studied using the method of phenomenological chiral Lagrangians. The expression of weak hadronic currents between pseudoscalar and axial-vector meson states is obtained.…
One-prong tau decays into final states involving kaons are studied with about 161k tau+tau- events collected by the ALEPH detector from 1991 to 1995. Charged kaons are identified by dE/dx measurement, while K0L's are detected through their…
We perform a measurement of the branching fractions for tau -> l gamma nu anti-nu (l= e, mu) decays for a minimum photon energy of 10 MeV in the tau rest frame using 430 fb^-1 of e^+ e^- collisions collected at the center-of-mass energy of…
The electric and magnetic dipole moments of the electron and of the muon provide stringent tests of the Standard Model and sensitive probes of new physics. By contrast, the corresponding dipole moments of the $\tau$ lepton remain weakly…
Presented are selected results of semileptonic B decays at BaBar. Two measurements of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$ are reported. One using moments of the hadronic-mass spectrum in inclusive $\bar{B} \to X_{c}…