منابع مشابه
The Massless Higher-loop Two-point Function
We introduce a new method for computing massless Feynman integrals analytically in parametric form. An analysis of the method yields a criterion for a primitive Feynman graph G to evaluate to multiple zeta values. The criterion depends only on the topology of G, and can be checked algorithmically. As a corollary, we reprove the result, due to Bierenbaum and Weinzierl, that the massless 2-loop 2...
متن کاملAnalytic Continuation of Massless Two-Loop Four-Point Functions
We describe the analytic continuation of two-loop four-point functions with one off-shell external leg and internal massless propagators from the Euclidean region of space-like 1→ 3 decay to Minkowskian regions relevant to all 1→ 3 and 2→ 2 reactions with one space-like or time-like off-shell external leg. Our results can be used to derive two-loop master integrals and unrenormalized matrix ele...
متن کاملMassless Two-loop Self-energy Diagram
ai−d πd ∫ dk1 d k2 [(k1 − k)2]a1 [(k2 − k)2]a2 [(k1 − k2)]3(k 2) a4(k2 1) a5 (1.1) in d-dimensional Euclidean momentum space. It has a long and interesting history. For many years, most of the information we had about perturbative quantum field theory was coming (directly or indirectly) from this integral. All massless three-loop self-energy integrals (with integer indices) reduce to 6 master i...
متن کاملTwo-Loop Electroweak NLL Corrections: from Massless to Massive Fermions
Recently the two-loop next-to-leading logarithmic (NLL) virtual corrections to arbitrary processes with massless external fermions have been calculated. Within the spontaneously broken electroweak theory the oneand two-loop mass singularities have been derived to NLL accuracy and expressed as universal correction factors depending only on the quantum numbers of the external particles. This talk...
متن کاملTwo-loop Soft Anomalous Dimensions with Massive and Massless Quarks
I present results for two-loop soft anomalous dimensions, which are derived from dimensionally regularized diagrams with eikonal quark lines and control soft-gluon emission in hard-scattering processes. Detailed results for the UV poles of the eikonal integrals are shown for massive quarks, and the massless limit is also taken. The construction of soft anomalous dimensions at two-loops allows s...
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ژورنال
عنوان ژورنال: The European Physical Journal C
سال: 2003
ISSN: 1434-6044,1434-6052
DOI: 10.1140/epjc/s2003-01389-7