Event shape criteria for single-lepton top signals

Abstract

Single-lepton plus jets signals from $t\bar t$ production at hadron colliders generally give more spherically symmetrical events than the principal backgrounds from $W$ production. We show that sphericity and aplanarity criteria, applied to lepton plus neutrino plus four jet final states at the Fermilab Tevatron $p\bar p$ collider, help to discriminate; they can be used either to validate an eventual top signal or simply to reduce background. An alternative circularity criterion in the transverse plane is less successful.

Standard Latex file, 8 pages. 3 figures, encoded using "uufiles", also submitted to hep-ph; uncompressed PS files or hardcopies available upon request. MAD/PH/777