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[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 ττ = (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 τντW 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] 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
[en] Since the initial measurements of the electron charge a century ago, experimenters have faced the persistent question as to whether elementary particles exist that have charges that are fractional multiples of the electron charge. I concisely review the results of the last 50 years of searching for fractional charge particles with no confirmed positive results. I discuss the question of whether more searching is worthwhile?
[en] Standard Model contributions to the electron, muon, and tau lepton anomalous magnetic moments, al = (gl - 2)/2, are reviewed and updated. The fine structure constant is obtained from the electron ge - 2 and used to refine the QED contribution to the muon gμ - 2. Recent advances in electroweak and hadronic effects on gμ - 2 are summarized. Examples of ''New Physics'' probed by the aμ Brookhaven experiment E821 are outlined. The prediction for aτ is also given
[en] We study the balance energy (Ebal) as a function of combined system mass for different colliding geometries, which range from central to semiperipheral ones. We find that Ebal follows a power law behavior (∝Aτ) at all colliding geometries. We also study the effect of momentum dependent interactions on Ebal as well as on its mass dependence. We find that the inclusion of momentum dependent interactions changes the value of τ drastically at peripheral geometries in agreement with other calculations.