EffectivepTcutoff for the isolated lepton background from bottom quark decay

There is a strong correlation between the ${\mathit{p}}_{\mathit{T}}$ and isolation of the lepton coming from B decay. Consequently the isolated lepton background from B decay goes down rapidly with increasing lepton ${\mathit{p}}_{\mathit{T}}$; and there is a ${\mathit{p}}_{\mathit{T}}$ cutoff beyond which it effectively vanishes. For the isolation cut of ${\mathit{E}}_{\mathit{T}}^{\mathit{A}\mathit{C}}$${\mathit{p}}_{\mathit{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 i s a g e t programs. Similar results are expected to hold at the Superconducting Super Collider energy as well.