The Search for VH → VWW standard model higgs production in the trilepton signature with 5.9fb<sup>-1</sup> of data from p$\bar{p}$ collisions at √s=1.96 GeV

Abstract

We present here the search for Standard Model V H → VWW → lll + ET (missing energy due to neutrinos) production, where V is a W or Z weak vector boson, which uses up to 5.9 fb-1 of integrated luminosity. This analysis has recently added to the CDF high-mass Higgs group three new signal topologies characterized by a tri-lepton signature, which are chosen to isolate the V H → VWW associated production signals in the three-lepton signature. As such, we define three new regions for a WH analysis, a ZH 1-jet analysis, and a ZH ≥ 2-jet analysis with which we expect to contribute an additional 5.8% (for mH = 165 GeV) acceptance to the current H → WW dilepton analysis. The ZH trilepton regions are defined by events passing a Z-boson selection: events having at least one lepton pairing (among three possible pairings) with opposite sign, same flavor, and a dilepton invariant mass within [76.0, 106.0] GeV–a ± 15 GeV window around the Z-boson mass. TheWH trilepton region is then defined as the set of trilepton events that are complement to those chosen by the Z-boson selection. These three new event topologies make a substantial contribution to the H → WW group result. As a measure of the sensitivity of this search, we compute the median expected limit on the at 95% confidence level (“C.L.”) on the production cross section (effectively the rate of production) for a StandardModel Higgs boson and report the result as a ratio to the theoretical production cross section. An observed limit ratio of one or less at a given mass would rule out the production of a Standard Model Higgs boson at that mass with 95% confidence. At mH = 165 GeV, the WH analysis expected limits reach 7.2 times the standard model cross section; the ZH 1-jet analysis is set at 29 times the expected standard model cross section; the ZH ≥ 2-jet analysis is set at 9.9 times the expected standard model cross section; and the combined trilepton analysis is set at 4.9 times the expected standard model cross section. We announce that the combination of this trilepton V H → VWW Higgs boson search and the previous CDF dilepton H → WW search achieves an expected median limit of 1.00 at 165 GeV/c2. The expected median limit of 1.00 indicates we anticipate a 50% probability of ruling out the existence of a Standard Model Higgs boson with a mass of 165 GeV/c2. This is the first time a single hadron collider experiment has achieved sensitivity to the production of a Standard Model Higgs boson. We do not see evidence for a significant signal of Higgs bosons in the data and place observed limits on the production of a Standard Model Higgs boson of 165 GeV/c2 at 1.08 times Standard Model production cross section. Matthew