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Manuscript Title: LOOPS: procedures for multiloop calculations in quantum field theory for system REDUCE.
Authors: L.R. Surguladze, F.V. Tkachov
Program title: LOOPS
Catalogue identifier: ABJO_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 55(1989)205
Programming language: Reduce.
Computer: ES - 1060.
Operating system: OS ES (VS2 COMPATIBLE).
RAM: 400K words
Word size: 32
Peripherals: disc.
Keywords: Quantum field theory, High energy physics calculations, Perturbation theory, Dimensional Regularization, Mutliloop Feynman Integral, Analytical calculations.
Classification: 4.4, 5.

Nature of problem:
Dimensionally regularized multiloop massless Feynman integrals of a propagator type (so called p-integrals), usually appearing in the tasks of the quantum field theory, in particular, high energy physics calculations are computed analytically here.

Solution method:
The algorithm, based on some identies, connecting different p-integrals and are true within dimensional regularization, is used.

LOOPS contain procedures for calculating only one- and two-loop p- integrals. For F-type diagrams (see fig.2, "LONG WRITE-UP") only scalar p-integrals, i.e. the integrals without free tensor indices are allowed. For the integrals the Laurent expansion in terms of Epsilon is calculated up to and including terms of the order O(Epsilon**5-l), where Epsilon is the deviation of the space-time dimension D from the physical dimension D o (D o is an arbitrary even positive number) within the dimensional regularization (D=D o - 2Epsilon) and 1 is the number of loops.

Running time:
It strongly depends on the topology and complexity of the calculated diagram and can fluctuate from a few seconds to 10**3 seconds and more for the most complex tasks for ES-1060 computer.