An effective p_T cutoff for the isolated lepton background from bottom quark decay

Abstract

There is a strong correlation between the p_T and isolation of the lepton coming from B decay. Consequently the isolated lepton background from B decay goes down rapidly with increasing lepton p_T and there is a p_T cutoff beyond which it effectively vanishes. For the isolation cut of E_T^AC<10 GeV, appropriate for the CERN Large Hadron Collider (LHC), the lepton p_T cutoff is 80 GeV. This can be exploited to effectively eliminate the B background from the like-sign dilepton channel appropriate for Majorana particle searches, as well as the unlike-sign dilepton and the single lepton channels appropriate for the top quark search. We illustrate this with a detailed analysis of the B background in these channels along with the signals at LHC energy using both parton level Monte Carlo and isaget programs. Similar results are expected to hold at the Superconducting Super Collider energy as well.