Search for Lepton-Photon Events at CDF Public Page |
We present results of a search for anomalous production of events
containing a charged lepton (either electron or muon) and a photon,
both with high transverse momentum, accompanied by additional
signatures, X, including missing transverse energy (MET) and
additional leptons and photons. We use the same kinematic selection
criteria as in a previous CDF search, but with a substantially larger
data set, 929 pb-1, a ppbar collision energy of 1.96 TeV, and
the upgraded CDF II detector. We find 163 Lepton+Photon+MET
events versus a standard model expectation of 150.6 +- 13.0
events. The level of excess observed in Run I, 16 events with an
expectation of 7.6 +- 0.7 events (corresponding to a 2.7 sigma
effect), is not supported by the new data. In the signature of
(ee/&mu&mu)+Photon+X we observe 74 events versus an
expectation of 65.1 +- 7.7 events. In this sample we find no
events with an extra photon and so find no events like the one
ee+&gamma&gamma+MET event observed in Run I. In the signature of
Electron+Muon+Photon+X we find no events versus an expectation
of 1.0 +- 0.3 events. In the signature of
Multi-Photon+Lepton+X we find no events versus an expectation
of 0.62 +- 0.15 events.
Selection Cuts for Lepton + Photon + X | |
---|---|
The Selection Cuts for Lepton+Photon+X. The kinematic
selection is set a priori - it is the same as criteria
used in the previous Run I CDF search (hep-ex/0202044),
and the same as used in recent CDF Run II publication on 305
pb-1(hep-ex/0605097)
PS or PDF, or JPG, | |
Lepton + Photon + Missing Transverse Energy Plots | |
The distributions for events in the Lepton+Photon+Missing
Transverse Energy sample (points) in a) the E_T of the
photon; b) the E_T of the lepton, c) the Missing Transverse
Energy, and d) the transverse mass of the Lepton+Photon-Missing
Transverse Energy system. The histograms show the expected SM
contributions, including estimated backgrounds from
misidentified photons and leptons. We find 163
Lepton+Photon+MET events versus a standard model expectation
of 150.6 +- 13.0 events. The level of excess observed in
Run I, 16 events with an expectation of 7.6 +- 0.7 events
(corresponding to a 2.7 sigma effect), is not supported by the
new data.
PS or PDF, or JPG, | |
Multi-Lepton + Photon Plots | |
The distributions for events in the Multiple Leptons +
Photon sample (points) in a) the E_T of the photon; b) the
E_T of the lepton, c) the 2-body mass of the dilepton system,
and d) the 3-body invariant mass of Leptons + Photon. The
histograms show the expected SM contributions. In the signature
of Multi-Lepton + Photon + X we observe 74 events
versus an expectation of 65.1 +- 7.7 events. In this
sample we find no events with an extra photon and so find no
events like the one ee+gg+MET event observed in Run I.
PS or PDF, or JPG, | |
Multi-Lepton + Photon Plots: missing transverse energy | |
The distributions in Missing Transverse Energy,
observed in the Multiple Leptons + Photon inclusive search for
muon pairs (Left) and electron pairs (Right). The histograms
show the expected SM contributions. In the Multi-Lepton + Photon + X
with MET > 25 GeV 3 events observed are consistent with
the SM expectation of 0.6 +- 0.1 events.
PS or PDF, or JPG, | |
Lepton+Photon+MET Summary table | |
A comparison of the numbers of events predicted by the
Standard Model and the observations for the
Lepton+Photon+Missing Transverse Energy search. The SM
predictions for the search are dominated by W+gamma and Z+gamma
production. Other contributions come from the tri-boson
processes W+gamma+gamma and Z+gamma+gamma, leptonic tau decays,
and misidentified leptons, photons, or Missing Transverse
Energy.
PS or PDF, or JPG, | |
Multi-Lepton + Photon Summary table | |
A comparison of the numbers of events predicted by the
Standard Model and the observations for the Multiple Leptons
+ Photon search. The SM predictions for the search are
dominated by Z+gamma production. Other contributions come from
the Z+gamma+gamma, and misidentified leptons and photons.
PS or PDF, or JPG, | |
Electron+Muon+Photon Summary table | |
A comparison of the numbers of events predicted by the
Standard Model and the observations for the
Electron+Muon+Photon search. The SM predictions for the
search are dominated by Z+gamma production. Other contributions
come from the W+gamma, Z+gamma+gamma, W+gamma+gamma, and
misidentified leptons and photons.
PS or PDF, or JPG, | |
Multi-Photon + Lepton Summary table | |
A comparison of the numbers of events predicted by the
Standard Model and the observations for the Multiple Photons
+ Lepton search. Dominant contribution comes from
misidentified photons. The SM predictions are dominated by
Z+gamma+gamma production.
PS or PDF, or JPG, | |
Additional Plots for Lepton+Photon+MET Search | |
Lepton+Photon+MET. The distributions for events in a)
H_T, the sum of the transverse energies of the lepton, photon,
jets and MET; b) the distance in eta-phi space between the
photon and lepton; c) the angular separation in phi between the
lepton and MET; and d) the invariant mass of the
Lepton+Photon system.
PS or PDF, or JPG, | |
Additional Plots for Lepton+Photon+MET Search in the Muon channel | |
Muon+Photon+MET. The distributions for events in
in a) the E_T of the photon; b) the P_T of the muon; c) the
missing transverse energy; and d) the transverse mass of the
Muon+Photon+MET.
PS or PDF, or JPG, | |
Muon+Photon+MET. The distributions for events in
a) H_T, the sum of the transverse energies of the muon,
photon, jets and MET; b) the distance in eta-phi space between
the photon and muon; c) the angular separation in phi between
the muon and MET; and d) the invariant mass of the
Muon+Photon system.
PS or PDF, or JPG, | |
Additional Plots for Lepton+Photon+MET Search in the Electron channel | |
Electron+Photon+MET. The distributions for events in
in a) the E_T of the photon; b) the E_T of the electron; c) the
missing transverse energy; and d) the transverse mass of the
Electron+Photon+MET.
PS or PDF, or JPG, | |
Electron+Photon+MET. The distributions for events in
a) H_T, the sum of the transverse energies of the electron,
photon, jets and MET; b) the distance in eta-phi space between
the photon and electron; c) the angular separation in phi between
the electron and MET; and d) the invariant mass of the
Electron+Photon system.
PS or PDF, or JPG, | |
Additional Plots for Multi-Lepton + Photon Search | |
Multi-Lepton + Photon. The distributions for events in a)
H_T, the sum of the transverse energies of the lepton, photon,
jets and MET; b) the distance in eta-phi space between
the photon and each of the two leptons.
PS or PDF, or JPG, | |
Additional Plots for Multi-Lepton + Photon Search: Muon Channel | |
Muon+Photon+MET. The distributions for events in a)
the E_T of the photon; b) the P_T of the muon, c) the 2-body
mass of the dimuon system, and d) the 3-body invariant mass of
Muons + Photon.
PS or PDF, or JPG, | |
Multi-Muon + Photon. The distributions for events in a)
H_T, the sum of the transverse energies of the muon, photon,
jets and MET; b) the distance in eta-phi space between
the photon and each of the two muons.
PS or PDF, or JPG, | |
Additional Plots for Multi-Lepton + Photon Search: Electron Channel | |
Electron+Photon+MET. The distributions for events in
a) the E_T of the photon; b) the E_T of the electron, c) the
2-body mass of the dielectron system, and d) the 3-body
invariant mass of Electrons + Photon.
PS or PDF, or JPG, | |
Multi-Electron + Photon. The distributions for events in a)
H_T, the sum of the transverse energies of the electron, photon,
jets and MET; b) the distance in eta-phi space between
the photon and each of the two electrons.
PS or PDF, or JPG, | |
Summary slide | |
Lepton+Photon+X summary slide
PS or PDF, or JPG, |