Tevatron experiments have recently set or improved limits on quark and lepton compositeness. Included here are results from p s = 1:8 TeV pp collider experiments D and CDF and from xed target neutrino experiment CCFR, who report limits on quark-quark, quark-lepton, and quark-neutrino compositeness, respectively.

Present measurements of b→cτν and b→uτν transitions differ from the standard model predictions of lepton flavor universality by almost 4σ. We examine new physics interpretations of this anomaly. An effective field theory analysis shows that minimal flavor violating models are not preferred as an explanation, but are also not yet excluded. Allowing for general flavor violation, right-right vecto...

The basis for the investigations on diffraction is provided by a large and interesting set of new experimental data. Indeed, the phenomenon of “hard” diffraction, where a hard probe has been proven to be consistent with a diffractive process, came first as an experimental surprise both at hadronhadron (Spp̄S, 88’, Tevatron 95’) and lepton-hadron (HERA, 94’) colliders. It is thus to be remarked t...

Neutrinoless tau-lepton decays into either three leptons (τ − → ℓ − 1 ℓ2ℓ3) or one lepton and one K 0 S meson(τ − → ℓ − K 0 S) where lepton ℓ means either an electron or muon, have been searched for using 48.6 fb −1 of data collected with the Belle detector at the KEKB e + e − collider. No evidence for candidate decays are found in any channel. Therefore we set 90% confidence level upper limits...

In a recent paper, eight semileptonic parameters were defined to specify the most general Lorentz-invariant spin correlation functions for tau semileptonic decays. The parameters were physically defined in terms of tau-decay partial-width intensities for polarized final states. This paper studies how these parameters can be simply measured at a tau/charm factory with longitudinally polarized be...

Within a field theoretical model where all damping width effects are treated self-consistently we study the changes of the spectral properties of ρ-mesons due to the finite damping width of the pions in dense hadronic matter at finite temperature. The corresponding effects in the di-lepton yields are presented. Some problems concerning the self consistent treatment of vector or gauge bosons are...

Bose-Einstein correlations and momentum distributions are calculated for a longitudinally expanding boson source, where the expanding system has a finite size in space-time rapidity. Such systems are physically realized in any of the single jets in high energy e + e − , lepton-hadron and hadron-hadron collisions as well as in high energy heavy ion collisions, where the projectile is not really ...

Group theoretical arguments seem to indicate the discrete symmetry S4 as the minimal flavor symmetry compatible with tribimaximal neutrino mixing. We prove in a model-independent way that indeed S4 can realize exact tribimaximal mixing through different symmetry breaking patterns. We present two models in which lepton tribimaximal mixing is realized in different ways and for each one we discuss...