Minijet veto: a tool for the heavy Higgs search at the LHC

Abstract

The distinct color flow of the $qq\to qqH,\; H\to W^+W^-$ process leads to suppressed radiation of soft gluons in the central region, a feature which is not shared by major background processes like $t\bar t$ production or $q\bar q \to W^+W^-$. For the leptonic decay of a heavy Higgs boson, $H\to W^+W^- \to \ell^+\nu \ell^-\bar\nu$, it is shown that these backgrounds are typically accompanied by minijet emission in the 20--40 GeV range. A central minijet veto thus constitutes a powerful background rejection tool. It may be regarded as a rapidity gap trigger at the semihard parton level which should work even at high luminosities.