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Manuscript Title: eett6f v. 1.0, a program for top quark pair production and decay into 6 fermions at linear colliders.
Authors: K. Kolodziej
Program title: eett6f v. 1.0
Catalogue identifier: ADRD_v1_0
Distribution format: tar.gz
Journal reference: Comput. Phys. Commun. 151(2003)339
Programming language: Fortran.
Computer: PC 800 MHZ Pentium III.
Operating system: Unix, Linux.
RAM: 1M words
Word size: 32
Keywords: e+e- annihilation, SM, Lowest order six-fermion reactions, ttbar production and decay, Elementary particle physics, Event simulation.
Classification: 11.2.

Nature of problem:
Description of e+e- -> 6 fermions processes relevant for a ttbar-pair production and decay at centre of mass energies typical for linear colliders; all six fermion reactions containing a b and bbar quarks and four other fermions of different flavours with a complete set of the Feynman diagrams in the lowest order of SM.

Solution method:
Matrix elements are calculated numerically with the helicity amplitude method. Constant widths of unstable particles are implemented by modifying mass parameters in corresponding propagators. The phase space integration is performed numerically utilizing a multi-channel Monte Carlo method.

Reactions containing fermions of the same flavour are not treated. No higher order effects are taken into account, except for assuming the fine structure constant and the strong coupling at appropriate scale and partial summation of the one particle irreducible loop corrections by introducing fixed widths of unstable particles.

Running time:
The running time depends strongly on a desired precision of the result. The results of the appended test run have been obtained on a 800 MHz Pentium III processor with the use of Absoft FORTRAN 90 compiler in 490 seconds. In order to obtain a precision level below one per mille a few million calls to the integrand are required. This results in a typical running time of several hours. The running time becomes much shorter for approximated cross sections.