We review world-average measurements of the tau lepton electroweak couplings, in both decay (including Michel parameters) and in production (Z → ττ and W → τ−ντ ). We review the searches for anomalous weak and EM dipole couplings. Finally, we present the status of several other tau lepton studies: searches for lepton flavor violating decays, neutrino oscillations, and tau neutrino mass limits.

We discuss the interaction of photons with neutrinos including two lepton loops. The parity violation in the γν → γν channel due to two lepton loops is substantially enhanced relative to the one lepton loop contribution. However there is no corresponding enhancement in the parity conserving amplitude in either the direct or the cross channel γγ → ν ¯ ν.

The minimal standard electroweak model yields approximately half the observed value of the KL-KS mass difference. Antisymmetric tensor fields incorporated into the standard model can provide the rest 0.5×(∆mLS)exp. The effective lepton–lepton, quark–lepton and quark–quark tensor interactions induced by the charged tensor particles are presented. Submitted to “Phys. Lett. B” E-mail: physfac2@bge...

Two models incorporating different forms of spontaneously broken quark-lepton symmetry are discussed. Both models are constructed so that quark-lepton symmetry can be broken at as low an energy scale as phenomenology allows, thus maximising their testability. The first model uses the Pati-Salam gauge group SU(4)⊗SU(2) L ⊗SU(2) R. The main analysis presented here concerns large threshold correct...

Now the bounds on the lepton-flavor violating (LFV) decay modes of tau lepton are being improved by the Belle experiment in the KEK B factory. In this paper the LFV decay of tau lepton is discussed in the supersymmetric seesaw model, using the current neutrino oscillation data.

We discuss the two-photon exchange contribution to observables which involve lepton helicity flip in elastic lepton-nucleon scattering. This contribution is accessed through the spin asymmetry for a lepton beam polarized normal to the scattering plane. We estimate this beam normal spin asymmetry at large momentum transfer using a parton model and we express the corresponding amplitude in terms ...

The study for lepton flavor violation combined with the neutrino oscillation may provide more information about the lepton flavor structure of the grand unified theory. In this paper, we study two lepton flavor violation processes , τ → μγ and Z → τμ, in the context of supersymmetric SO(10) grand unified models. We find the two processes are both of phenomenological interest. In particular the ...

General expressions for the double–lepton polarizations in the B → Kl+l− decay are obtained, using model independent effective Hamiltonian, including all possible interactions. Correlations between the averaged double–lepton polarization asymmetries and the branching ratio, as well as, the averaged single–lepton polarization asymmetry are studied. It is observed that, study of the double–lepton...

We study the tri–lepton signal for supersymmetric particle searches at the Teva-tron including the CP phases Φ µ and Φ 1 and the production–decay spin correlations. The phases affect very strongly the production rate and the branching fractions of the leptonic chargino and neutralino decays and, as a result, could lead to a sharp drop in the tri–lepton signal rate. We demonstrate the importance...