5 papers
Threshold expansion of the sunset diagram
A. I. Davydychev, V. A. Smirnov
By use of the threshold expansion we develop an algorithm for analytical evaluation, within dimensional regularization, of arbitrary terms in the expansion of the (two-loop) sunset…
Small-threshold behaviour of two-loop self-energy diagrams: some special cases
F. A. Berends, A. I. Davydychev, V. A. Smirnov
An algorithm to construct analytic approximations to two-loop diagrams describing their behaviour at small non-zero thresholds is discussed. For some special cases (involving two d…
Small-threshold behaviour of two-loop self-energy diagrams: two-particle thresholds
F. A. Berends, A. I. Davydychev, V. A. Smirnov
The behaviour of two-loop two-point diagrams at non-zero thresholds corresponding to two-particle cuts is analyzed. The masses involved in a cut and the external momentum are assum…
Zero-threshold expansion of two-loop self-energy diagrams
F. A. Berends, A. I. Davydychev, V. A. Smirnov +1
An algorithm is constructed to derive a small momentum expansion for two-loop two-point diagrams in all cases where, due to the presence of physical thresholds, there are singulari…
Large momentum expansion of two-loop self-energy diagrams with arbitrary masses
A. I. Davydychev, V. A. Smirnov, J. B. Tausk
For two-loop two-point diagrams with arbitrary masses, an algorithm to derive the asymptotic expansion at large external momentum squared is constructed. By using a general theorem…