Related papers: Lepton Universality, |V_{us}| and search for secon…
We review world-average measurements of the tau lepton electroweak couplings, in both decay (including Michel parameters) and in production ($Z^0\to \tau^+\tau^-$ and $W^-\to\tau^-\nubar_\tau$). We review the searches for anomalous weak and…
A preliminary measurement of the branching fraction of the tau- -> 3h-2h+nu decay (h= pi, K$) with the BaBar detector is found to be {8.52 +/- 0.09 +/- 0.40} x 10E-4, where the first error is statistical and the second is systematic. The…
The pure leptonic or semileptonic character of tau decays makes them a good laboratory to test the structure of the weak currents and the universality of their couplings to the gauge bosons. The hadronic tau decay modes constitute an ideal…
A search for the neutrinoless, lepton-flavor violating decay of the tau lepton into three charged leptons has been performed using an integrated luminosity of 468 fb^-1 collected with the BABAR detector at the PEP-II collider. In all six…
The B Factories have generated a large amount of new results on the tau lepton. The present status of some selected topics on tau physics is presented: charged-current universality tests, bounds on lepton-flavour violation, the…
Using data collected with the BaBar detector between 1999 and 2001, we describe a preliminary search for the neutrinoless decay Tau to Mu Gamma. This data sample includes data collected both on and off the Upsilon(4S) resonance and…
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 present status of some selected topics on tau physics is presented: charged-current universality tests, bounds on lepton-flavour violation, the determination of alpha_s from the inclusive tau hadronic width, the measurement of |V_{us}|…
A search for the neutrinoless, lepton-flavor violating decay of the tau lepton into three charged leptons has been performed using 376 fb^{-1} of data collected at an e^+e^- center-of-mass energy around 10.58 GeV with the BaBar detector at…
Precise measurements of the lepton properties provide stringent tests of the Standard Model and accurate determinations of its parameters. We overview the present status of tau physics, highlighting the most recent developments, and discuss…
We present a search for the decay B+ -> tau+ nu using 383x10^6 BBbar pairs collected at the Y(4S) resonance with the BABAR detector at the SLAC PEP-II B-Factory. A sample of events with one reconstructed semileptonic B decay (B- -> D0 l nu…
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…
This paper describes a measurement of the Michel parameters, \eta, \rho, \xi, \xi\delta, and the average \nu_{\tau} helicity, h_{\nu_{\tau}}, in tau lepton decays together with the first measurement of the tensor coupling in the weak…
The Belle and Belle II experiments have collected a 1.4 ab$^{-1}$ sample of $e^+e^-$ collision data at centre-of-mass energies near the $\Upsilon (nS)$ resonances, of which 424 fb$^{-1}$ were collected at Belle II in Run1 (2019--2022). We…
We present an overview of searches fo violation of lepton flavor universality with focus on low energy precision probes using pions, kaons, tau leptons, and nuclear beta decays. The current experimental results are reviewed, the theoretical…
The Standard Model predicts that the electroweak couplings to the three charged leptons are identical. However, in the last decade, experimental measurements have suggested that semileptonic processes involving taus could have a slightly…
A search for the lepton flavour violating decays $\tau^- \to l^- K^0_{\scriptscriptstyle S}$ ($l = e$ or $\mu$) has been performed using a data sample corresponding to an integrated luminosity of 469 ${fb}^{-1}$, collected with the…
We search for the rare leptonic decay B+ --> tau+ nu_tau in a sample of 232x10^6 BBbar pairs collected with the BABAR detector at the SLAC PEP-II B-Factory. Signal events are selected by examining the properties of the B meson recoiling…
We have searched for tau lepton decays, tau- -> Lambda-bar pi- and tau- -> Lambda pi-, that simultaneously violate the conservation of the lepton and baryon number using a data sample of 154 fb^{-1} collected with the Belle detector at the…
The usage of polarimetry and spin-correlation tests to determine the {\em complete Lorentz structure} of the tau lepton's charged and neutral-current couplings is reviewed. The emphasis is on tests for ``something'' in a $(V-A) + $…