Trilepton Higgs boson signal at hadron colliders

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 boson. This strategy can be utilized successfully for the standard model (SM) Higgs boson as well as nonstandard Higgs bosons which break electroweak symmetry but have little to do with fermion mass generation. The trileptons come from Wh production followed by W→hWWW(*)→3l decays. A SM Higgs trilepton signal would be difficult to detect at the Fermilab Tevatron collider: with 100fb^-1 of data, only a 3{σ} signal above background can be achieved after cuts if 140GeV<m_hₛₘ⁰<175GeV. Some discrimination of signal over background can be gained by analyzing the opposite sign dilepton pT distributions. At the CERN LHC with 30 (100)fb^-1 a clear discovery above the 5{σ} level is possible for a Higgs boson mass in the range 140--185 (125--200) GeV. Prospects for a trilepton Higgs boson discovery are greatly improved for models with nonstandard Higgs boson sectors where a Higgs boson couples preferentially to vector bosons rather than to fermions.