W+gamma and Z+gamma production blessed results for Winter 2004


The analysis was performed by
Al Goshaw, Michael Kirby (Duke University)
Helen Hayward,, Beate Heinemann (Liverpool University)
and Naho Tanimoto (Okayama University)
Event criteria for W+gamma

Electron
Et (transverse energy) > 25GeV, |eta(electron)|<1.1
Muon
Pt (transverse momentum) > 20GeV, |eta(muon)|<1.1
Neutrino MEt (missing transverse energy) > 25 GeV (electron analysis), 20 GeV (muon analysis)
Transverse mass(electron, neutrino)
30 < Mt < 120 GeV
Photon
Et(transverse energy) > 7 GeV,  |eta(photon)|<1.1


Wgamma events yields

Central : Luminosity 202 [pb-1]
            (stat.)±(sys.)
signal MC 180.51 ± 2.08 ± 10.11
W+jet Backgound
49.52 ± 0.10 ± 14.95
Zgamma
22.37 ± 0.38 ± 1.20
Wgamma-> tau nu gamma
3.23 ± 0.24 ± 0.17
total SM+BG
255.63 ± 2.13 ± 26.43
Data
259


Cross section for Et(gamma)>7 GeV and DeltaR(lepton,gamma)>0.7:

sigma(Wgamma) x BR(W->lepton + nu)
19.7 ± 1.7 (stat.) ± 2.0(sys.) ± 1.1 (lum.)
Theory : sigma(Wgamma) x BR(W-> lepton + nu)  19.3 ± 1.4 (sys.) [pb]

Event criteria for Z+gamma

Electron
Et (transverse energy) > 25GeV, |eta(electron)|<2.8
central EM calorimeter (CEM) covers |eta|< 1.1 and plug calorimeter covers 1.2 < |eta|<2.8
Muon
Pt (transverse energy) > 20GeV, |eta(muon)|<1.1
Invariant mass(lepton,lepton)
M > 40 GeV
Photon
Et(transverse energy) > 7 GeV,  |eta(photon)|<1.1


Zgamma events yields

Central : Luminosity 202 [pb-1]
            (stat.)±(sys.)
signal MC 65.76 ± 3.76
Z+jet Backgound
4.44 ± 1.33
other BG
0.26 ± 0.20
total SM+BG
70.46 ± 4.00
Data
69


Cross section for Et(gamma)>7 GeV and DeltaR(lepton,gamma)>0.7

sigma(Zgamma) x BR(Z->lepton + lepton)
5.3 ± 0.6 (stat.) ± 0.3(sys.) ± 0.3 (lum.)
Theory : sigma(Zgamma) x BR(Z-> lepton + lepton)  5.4 ± 0.3 (sys.) [pb]

Kinematic Distributions Wgamma
Zgamma
Et(gamma) photonEt
gif | eps
photonEt
gif | eps
Et(gamma) on log scale photonEt(central)logscale
gif | eps
photonEt(central)logscale
gif | eps
Delta R(lepton, photon) dR(central e, gamma)
gif | eps
dR(central e, gamma)
gif | eps
Wgamma: Transverse mass (lepton, neutrino)
Zgamma: Di-lepton invariant mass
Mt(l, nu)
gif | eps
Mt(l, nu)
gif | eps
Wgamma: Cluster transverse mass(lepton, photon, neutrino)
Zgamma: 3-body-mass(lepton, lepton, neutrino)
ctm(l,gamma,nu)
gif | eps
ctm(l,gamma,nu)
gif | eps
Wgamma: Cluster transverse mass vs transverse mass
Zgamma: 3-body vs dilepton mass
mt vs ctm
gif | eps
mt vs ctm
gif | eps
Charge signed rapidity difference


Last Updated March 10, 2004
Beate Heinemann(beate@fnal.gov) (Liverpool University)