Irreducible QCD backgrounds to top searches in semi-leptonic final states at the Next Linear Collider
Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, UK (e-mail: firstname.lastname@example.org)
Received: 12 January 1999 / Revised version: 24 March 1999 / Published online: 20 May 1999
At future electron-positron colliders, one of the largest irreducible backgrounds to top searches in the channel `4 jets + lepton + missing energy' comes from QCD events of order . We compute here such processes exactly at the parton level by resorting to 2 6 matrix elements exploiting helicity amplitude techniques. We adopt a typical selection procedure based on the tagging of a high momentum and separated lepton. We finally outline kinematic differences between signal and background events that can be exploited to further reduce such a QCD noise.