537 research outputs found

    Efficient Algorithm for Perturbative Calculation of Multiloop Feynman Integrals

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    We present an efficient algorithm for calculating multiloop Feynman integrals perturbatively.Comment: Author Information under http://www.physik.fu-berlin.de/~kleinert/institution.html . Latest update of paper also at http://www.physik.fu-berlin.de/~kleinert/29

    Evaluating multiloop Feynman integrals by Mellin-Barnes representation

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    The status of analytical evaluation of double and triple box diagrams is characterized. The method of Mellin-Barnes representation as a tool to evaluate master integrals in these problems is advocated. New MB representations for massive on-shell double boxes with general powers of propagators are presented.Comment: 5 pages, Talk given at the 7th DESY workshop on Elementary Particle Theory, "Loops and Legs in Quantum Field Theory", April 25-30, 2004, Zinnowitz, Germany, to appear in the proceeding

    Maximal Cuts in Arbitrary Dimension

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    We develop a systematic procedure for computing maximal unitarity cuts of multiloop Feynman integrals in arbitrary dimension. Our approach is based on the Baikov representation in which the structure of the cuts is particularly simple. We examine several planar and nonplanar integral topologies and demonstrate that the maximal cut inherits IBPs and dimension shift identities satisfied by the uncut integral. Furthermore, for the examples we calculated, we find that the maximal cut functions from different allowed regions, form the Wronskian matrix of the differential equations on the maximal cut.Comment: typos corrected, more references adde

    On the Resolution of Singularities of Multiple Mellin-Barnes Integrals

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    One of the two existing strategies of resolving singularities of multifold Mellin-Barnes integrals in the dimensional regularization parameter, or a parameter of the analytic regularization, is formulated in a modified form. The corresponding algorithm is implemented as a Mathematica code MBresolve.mComment: LaTeX, 10 page
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