CompHEP-PYTHIA interface: integrated package for the collision events generation based on exact matrix elements

CompHEP, as a partonic event generator, and PYTHIA, as a generator of final states of detectable objects, are interfaced. Thus, integrated tool is proposed for simulation of (al-most) arbitrary collision processes at the level of detectable particles. Exact (multiparti-cle) matrix elements, convolution with structure functions, decays, partons hadronization and (optionally) parton shower evolution are basic stages of calculations. The PEVLIB library of event generators for LHC processes is described. of matrix elements of hard subprocesses are built in. It means that matrix elements are stored as formulas. Furthermore, the matrix element squared | M | 2 is represented by means of some function modelling the behaviour of the integrand to get effective Monte-Carlo integration and events generation. Thus, as one can see, mainly 2 → 2 subprocesses are included in these data bases.