[en] The precision of τ lifetime measurements have increased remarkably in the last several years. The techniques which lead to these results are summarized and compared, together with results obtained by different experiments from use of these methods. By combining the recent, and previous lifetime values an updated world average lifetime of τ_τ = (291.7 ± 1.6) fs is obtained, which is in good agreement with the prediction derived from the τ electronic branching ratio through the assumption of τ-μ lepton universally

[en] In this paper the author discusses the issue of universality with respect to the tau particle. Present work is trying to attack this by looking at τν_τW and Zτ bar τ couplings. Some models predict that non-universality will be such a small effect that it may be only tractable with a device such as a tau-charm factory. The issue of universality has impacts in other electroweak reactions, and in many models. The observation of such effects may require very high luminosity however

[en] We present a review of BaBar results on e⁺e^- → hadrons using the initial state radiation technique. Cross sections over the √s range from threshold to 4-5 GeV, with very small point-to-point systematic errors, are presented for the π⁺π^-π⁰, 2(π⁺π^-), 2(K⁺K^-), 3(π⁺π^-), 2(π⁺π^-)2π⁰, 2(π⁺π^-)K⁺K^-, and p(bar p) final states. The preliminary results of e⁺e^- → K⁺K^-π⁺π^- and e⁺e^- → K⁺K^-π⁰π⁰ cross sections are also presented

[en] Based on 3.26 fb^-1 data sample collected at CLEO III, we study the decay τ^- a K⁺ K^- π^- ν_τ and improve the measurement of the branching ratio B(τ^- a K⁺ K^- π^- ν_τ) = (1.59 ± 0.06 ± 0.13) x 10^-3, the results preliminary

[en] A method of the τ lepton lifetime measurement improving the present accuracy by a factor of about two is reported. The value of an upper limit on the relative lifetime difference between positive and negative τ leptons is obtained. These results are based on 711fb^-1 of data collected at the Y(4S) resonance.

[en] Anomalous magnetic moment of the electron, muon and tau are given by theoretical and experimental analysis. Magnetic moment is related to the charge and the mass of the corresponding lepton. Using the concept of the helical motion of the charge of the electron, we obtained first the expression of the magnetic moment that is analogous to the anomalous magnetic moment of the electron in the order of the fine structure constant. Later we used the convention of fractional charge of the electron to step ahead in the quantum domain from the semi-classical approach. The masses of leptons are arranged in a α-quantized manner by MacGregor in terms of mass of the electron. Using those relations we have reproduced the magnetic moment of muon and tau and they are in good agreement with contemporary results. (author)

[en] We report the results of search for the neutrinoless lepton-flavor violating decay of the tau lepton into three charged leptons, 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 the PEP-II. In all six decay modes considered, the number of events found in data are compatible with the background expectations. Upper limits on the branching fractions are set in the range (4-8) x 10^-8 at 90% confidence level.

[en] The present status of the tau one prong problem is reviewed. Emphasis is placed on recent published branching fraction measurements, the status and implications of tau lifetime measurements, and measurements which constrain the sum of branching fractions to be unity

[en] The status of the Monte Carlo programs for the simulation of the τ-lepton production and decay in high energy accelerator experiments is reviewed. In particular, the status of the following packages is discussed: (i) TAUOLA for τ-lepton decay and PHOTOS for radiative corrections in decays, (ii) MC-TESTER for universal tests of the Monte Carlo programs describing particle decays, (iii) KORALB, KORALZ, KKMC packages for τ-pair production in e⁺e^- collisions, and (iv) universal interface of TAUOLA for the decay of τ-leptons produced by 'any' generator

[en] We have searched for the violation of baryon number B and lepton number L in the (B - L)-conserving modes τ^- → (bar Λ)π^- and τ^- → (bar Λ)K^- as well as the (B - L)-violating modes τ^- → Λπ^- and τ^- → ΛK^- using 237 fb^-1 of data collected with the BaBar detector at the PEP-II asymmetric-energy e⁺e^- storage rings. We do not observe any signal and we determine preliminary upper limits on the branching fractions Β(τ^- → (bar Λ)π^-) < 5.9 x 10^-8, Β(τ^-→ Λπ^-) < 5.8 x 10^-6, Β(τ^- → (bar Λ)K^-) < 7.2 x 10^-8, and Β(τ^- → ΛK^-) < 15 x 10^-8 at 90% confidence level