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Manuscript Title: Recursive numerical integration of multi-particle phase space with peripheral matrix element.
Authors: P. Pirila, E. Byckling
Program title: PERIPHERAL PHASE SPACE INTEGRAL
Catalogue identifier: AAUD_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 4(1972)117
Programming language: Fortran.
Computer: UNIVAC 1108.
Operating system: EXEC 8.
RAM: 21K words
Word size: 36
Keywords: Elementary, High energy, Particle physics, Phase space integral, Peripheral, Recursive integration, Cross section.
Classification: 11.2.

Nature of problem:
The program calculates the total cross section of a multiparticle final state as a function of total energy, when the matrix element is of the form exp(a1t1 + a2t2 +...+ an-1tn-1). This cross section is proportional to the volume of peripheral phase space.

Solution method:
The program is based on a recursive integration formula. At each recursion step the same integrand is integrated over many different integration areas, which are two-dimensional and bounded by a hyperbola and a straight line. The two-dimensional integrals are calculated by a method based on Simpson's formula.

Restrictions:
Mutliplicity of the final state between 3 and 20.

Running time:
2 min for about 5 per cent accuracy, multiplicities 3-8 and 100 energy values.