Searches for Higgs in H -> WW(*) -> ee/emu/mumu final states

These searches select events with two isolated, high pT leptons (criteria given below) and significant missing ET (MET). In addition, requirements are made to reject Z/gamma* Drell-Yan processes and the Standard Model WW background. The latter is suppressed by exploiting the spin correlations in the WW* decay. The backgrounds tend to give dilepton pairs which are back-to-back in the plane transverse to the beam, while the signal decays give leptons which have a positive correlation in their direction. The tables show comparisons between predicted backgrounds and observed event yields in data, and the figures compare the D(phi) distributions for backgrounds and signal.

Lepton ID and analysis requirements

Lepton kinematic selections

ee final state
  • e1: pT > 15 GeV
  • e2: pT > 12 GeV
  • |eta| < 1.3
emu final state
  • e: pT > 12 GeV
  • mu: pT > 7 GeV
  • |etae| < 1.3, |etamu| < 2
mumu final state
  • mu1: pT > 20 GeV
  • mu2: pT > 10 GeV
  • |eta| < 2


We first show the combined result for all three final states (ee/emu/mumu: D0 note 4225) followed by individual analysis (ee/emu: D0 note 4207; mumu: D0 note 4223)

Combined limit on sxB(H->WW)

Higgs production cross section times BR(H->WW) excluded with the current D0 data
(and LEP experiments), along with the expectations from various models.
This result is a combination of the ee, emu and mumu analyses.

(.eps version)


H -> WW(*) -> ee
Signal efficiencies, predicted background, and observed yields as function of
(the Higgs mass dependent) event selection requirements


Higgs signal efficiency, ee

Cut flow table, ee
Table 13: Expected number of background events and the number of observed
data events
at each step of the selection procedure for a Higgs mass of 160 GeV

D(phi) plots, ee
(.eps versions: 1, 2, 3, 4, 5, 6, 7, 8, 9)

H -> WW(*) -> emu
Signal efficiencies, predicted background, and observed yields as function of
(the Higgs mass dependent) event selection requirements


Higgs signal efficiency, emu

Cut flow table, emu
Table 19: Expected number of background events and the number of observed
data events
at each step of the selection procedure for a Higgs mass of 160 GeV

D(phi) plots, emu
(.eps versions: 1, 2, 3, 4, 5, 6, 7, 8, 9)

Combined limit plot, ee+emu

Cross section times BR excluded with the current D0 ee+emu data
(and LEP experiments), along with the expectations from various models.

(.eps version)


H -> WW(*) -> mumu
Signal efficiencies, predicted background, and observed yields as function of
(the Higgs mass dependent) event selection requirements

 

Higgs signal efficiency, mumu (tab.5)
Higgs signal efficiency, mumu (tab.6)

Cut flow tab.9, mumu


E_T missing distribution
ET missing distribution in mumu final states
(.eps version)

D(phi) plots, mumu
Azimuthal opening angle D(phi) between two muons after various cuts
(from top left to bottom right): Z selection, invariant mass, ET missing and ETHAD

(.eps version)

Limit plot, mumu
Higgs production cross section times BR(H->WW) excluded with the current D0 mumu data
(.eps version)


DZero Higgs group results web pages are here
DZero Higgs group home page is here


Contact persons: Avto Kharchilava, John Hobbs