A new approach to multi-jet calculations in hadron collisions

We present an algorithm to evaluate the exact, tree-level matrix elements for multi-parton processes in QCD, We tested this technique, based on the recursive evaluation of the S-matrix, on processes such as gg --> n gluons and q (q) over bar--> n gluons, with n up to 9. The summation over colour configurations is designed to allow the construction of parton-level event generators suitable to interfacing with a parton-shower evolution including the effects of colour coherence. This leads to a fully exclusive, hadron-level description of multi-jet final states, accurately incorporating the dynamics of large jet-jet separation angles. Explicit results for the total rates and differential distributions of processes with eight final-state partons are given. (C) 1999 Elsevier Science B.V.