Trilepton Higgs signal at hadron colliders

Abstract

Determining the origin of electroweak symmetry breaking will be one of the primary functions of high energy colliders. We point out that most Higgs boson searches pursued at hadron colliders require Yukawa interactions either in the production or the decay of a Higgs boson. We propose a trilepton Higgs boson search based only upon the gauge interactions of the Higgs. This strategy can be utilized successfully for the standard model (SM) Higgs boson as well as non-standard Higgs bosons which break electroweak symmetry but have little to do with fermion mass generation. The trileptons come from Wh production followed by Wh -> WWW^(*) -> 3l decays. A SM Higgs trilepton signal would be difficult to detect at the Tevatron collider: with 100 fb^{-1} of data, only a $3σ$ signal above background can be achieved after cuts if 140 GeV < mh < 175 GeV. Some discrimination of signal over background can be gained by analyzing the opposite sign dilepton pT distributions. At the LHC with 30 (100) fb^{-1} a clear discovery above the $5σ$ level is possible for a Higgs mass in the range 140-185 (125-200) GeV. Prospects for a trilepton Higgs discovery are greatly improved for models with non-standard Higgs sectors where a Higgs boson couples preferentially to vector bosons rather than to fermions.