Six-jet production at lepton colliders

We study electron-positron annihilations into six jets at the parton level in perturbative Quantum Chrome-Dynamics (QCD), via the elementary processes e(+)e(-) --> q (q) over bar gggg, e(+)e(-) --> q (q) over bar q'(q) over bar'gg and e(+)e(-) --> q (q) over bar q'(q) over bar'q "(q) over bar ", for massive quarks q, q' and q " and massless gluons g. Several numerical results of phenomenological relevance are given, at three different collider energies and for a representative selection of jet clustering algorithms. We also present helicity amplitudes and colour factors needed for the tree-level calculation. (C) 1999 Elsevier Science B.V.