ar X iv : h ep - p h / 02 05 01 9 v 1 2 M ay 2 00 2 Double – Logarithmic Two – Loop Self – Energy Corrections to the Lamb Shift

ar X iv : h ep - p h / 02 05 01 9 v 2 1 0 Ju l 2 00 2 Double – Logarithmic Two – Loop Self – Energy Corrections to the Lamb Shift

Self-energy corrections involving logarithms of the parameter Zα can often be derived within a simplified approach , avoiding calculational difficulties typical of the problematic non-logarithmic corrections (as customary in bound-state quantum electrodynamics, we denote by Z the nuclear charge number, and by α the fine-structure constant). For some logarithmic corrections, it is sufficient to ...

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...

ar X iv : h ep - p h / 00 05 02 8 v 1 3 M ay 2 00 0 Off - forward gluonometry .

We explore the deeply virtual Compton scattering process at NLO with the emphasis on the measurement of the tensor gluon skewed distributions. We recalculate the one-loop coefficient function and give two-loop results for anomalous dimensions and exclusive evolution kernels required for studying the logarithmic scaling violation. We evaluate weighted cross sections which give direct access to t...

ar X iv : h ep - p h / 99 05 24 9 v 2 1 2 M ay 1 99 9 BI - TP 99 / 12 Two - loop self - energy master integrals on shell

Analytic results for the complete set of two-loop self-energy master integrals on shell with one mass are calculated.

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