ar X iv : h ep - p h / 01 05 28 2 v 1 2 7 M ay 2 00 1 Theoretical issues at LEP 2 and LC

ar X iv : h ep - p h / 02 05 01 6 v 1 2 M ay 2 00 2 Scalar a 0 ( 980 ) meson in φ → π 0 ηγ decay

ar X iv : h ep - p h / 06 05 13 6 v 1 1 1 M ay 2 00 6 Lepton Flavor Violating τ and μ decays

ar X iv : h ep - p h / 01 05 03 3 v 1 3 M ay 2 00 1 Threshold η and η ′ electroproduction off nucleons 1

The electroproduction of η and η ′ mesons on the proton and the neutron is investigated at tree level within the framework of U (3) chiral perturbation theory. In addition to the Born terms low-lying resonances such as the vector mesons and J P = 1/2 + , 1/2 − baryon resonances are included explicitly and their contributions are calculated. Results for the separated differential cross sections ...

ar X iv : h ep - p h / 04 05 11 9 v 1 1 3 M ay 2 00 4 The Lorentz and CPT violating effects on the charged

ar X iv : h ep - p h / 01 05 14 1 v 1 1 5 M ay 2 00 1 Nonperturbative corrections to the quark self - energy

Nonperturbative self-energy of a bound quark is computed gauge-invariantly in the framework of background perturbation theory. The resulting ∆m 2 q is negative and is a universal function of string tension and current quark mass. The shift of hadron mass squared, M 2 , due to ∆m 2 q is negative, large for light quarks, and solves the long-standing problem of Regge intercepts in relativistic qua...