Related papers: Lepton Universality, |V_{us}| and search for secon…
Decay rate, forward-backward asymmetry and polarization asymmetries of final state leptons in B-> K_{1}tau ^{+}tau ^{-}, where K_{1} is the axial vector meson, are calculated in Standard Model and in the universal extra dimension (UED)…
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. We investigate the decays of a Tau-lepton into three charged leptons (Tau ->…
Recent BABAR and Belle results on rare B decays involving photons or lepton pairs are reviewed. New preliminary limits from both experiments for B-->rho gamma and B-->omega gamma, and from BABAR for B --> K nu nu and B --> tau nu are…
By exploiting the relatively long lifetime of the tau lepton, we propose several novel methods for searching for new physics at an electron-positron collider. We consider processes that involve final states consisting of a tau lepton pair…
We have searched for the violation of baryon number B and lepton number L in the (B-L)-conserving modes tau- -> anti-Lambda0 pi- and tau- -> anti-Lambda0 K- as well as the (B-L)-violating modes tau- -> Lambda0 pi- and tau- -> Lambda0 K-…
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…
I review the current status of measurements involving semi-tauonic $B$ meson decay at the $B$-factories. I briefly discuss the experimental methods and highlight the importance of background contributions especially from poorly understood…
We present a search for the radiative leptonic decays B+ -> e+ nu gamma and B+ -> mu+ nu gamma using data collected by the BABAR detector at the PEP-II B factory. We fully reconstruct the hadronic decay of one of the B mesons in Upsilon(4S)…
A preliminary measurement of the branching fraction B(tau- --> K0 pi- nu) is made using 384.6 fb-1 of e+e- collision data provided by the PEP-II collider, operating primarily at sqrt(s)=10.58 GeV, and recorded using the BaBar detector. From…
We have searched for the lepton-number violating processes B+ -> h- l+ l+ with h- = K-/pi- and l+ = e+/mu+, using a sample of 471+/-3 million BBbar events collected with the BaBar detector at the PEP-II e+e- collider at the SLAC National…
We present the results of a search for charged-lepton-flavor violating decays $\tau^{-} \rightarrow \ell^{-}K_{S}^{0}$, where $\ell^{-}$ is either an electron or a muon. We combine $e^+e^-$ data samples recorded by the Belle II experiment…
We present the first comprehensive tests of light-lepton universality in the angular distributions of semileptonic $B^0$-meson decays to charged spin-1 charmed mesons. We measure five angular-asymmetry observables as functions of the decay…
The NA62 experiment at CERN aims to use rare kaon decays to search for new phenomena beyond the Standard Model. During the current short term phase (data taking completed in years 2007-8), the ratio $R_K = \Gamma(K^+ \rightarrow e \nu_e…
We search for lepton-flavor-violating and lepton-number-violating tau decays into a lepton (l = electron or muon) and two charged mesons (h, h' = pion or Kaon) using 854 fb^{-1} of data collected with the Belle detector at the KEKB…
We have searched for decays that violate both lepton and baryon number using data collected by the Belle detector at the KEKB asymmetric e^+e^- collider. No signals are found in tau^- -> \bar{p} gamma, tau^- -> \bar{p} pi^0, tau^- ->…
The tau -> mu nu nu branching ratio has been measured using data collected from 1990 to 1995 by the OPAL detector at the LEP collider. The resulting value of B(tau -> mu nu nu) = 0.1734 +- 0.0009(stat) +- 0.0006(syst) has been used in…
An important prediction of the standard model is the universality of the gauge interactions of the three generation of charged leptons. Violation of this universality would be a clean evidence of new physics (NP) beyond the standard model.…
We discuss the potential of $\tau$-charm and B factories for the search of new physics through the study of rare $\tau$ decays. We consider decays that involve the violation of lepton flavour conservation. Such decays bear a close…
The recent significant progress on both the experimental and theoretical sides on the study of leptonic and semileptonic kaon decays allows to precisely test the Standard Model. Here we present results for the determination of Vus from…
The B0 lifetime has been measured with a sample of 23 million BBbar pairs collected by the BaBar detector at the PEP-II e+e- storage ring during 1999 and 2000. Events from the semileptonic decay B0 --> D*- l+ nu have been selected with a…