DELPHI LEP183 EVENTS, f-fbar-gamma
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D E L P H I |
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Events from 183 GeV |
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f fbar (gamma) events |
Below is a sample of events taken by the DELPHI experiment during
the period where the LEP accelerator was running at 183 GeV energy in 1997.
To get the full size picture of an event (in Postscript), click on the icon.
To get its description, click on the label below the icon.
Events :
e+ e- --> f fbar (beam energy) :
- r080968e001896,
(Mu Mu) event
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Mu+ Mu- event with both muons clearly identified (MIP in the Hadron Calorimeter,
hits in the muon chambers) and with total energy compatible with the beam.
- r080966e001155,
(e+ e-) event
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Candidate e+ e- event at beam energy.
The electrons are identified by the associated showers in the HPC.
Z0 radiative return :
e+ e- --> Z0 gamma, ISR+FSR :
- r080931e001435,
(Mu Mu gamma) + gamma
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Candidate Z0 gamma event, where the Z decays into a Mu-Mu-gamma.
Both muons are identified as MIP in the Hadron Calorimeter,
one has associated hits in the barrel Muon Chambers,
the other in the Forward and the Surround Muon Chambers.
In addition, the event has a photon showering in the HPC and close (but not
superposed) to the Mu-.
The (Mu+Mu-) pair has a mass of approximately 70 GeV, but the mass of the
(Mu+Mu-gamma) system is about 93 GeV, in good agreement with a Z0.
It can be interpreted as a Z0 decaying into Mu-Mu, accompanied by a photon of
final state radiation.
The missing vector is compatible with a photon emitted at 0.7 degree
polar angle and an energy of 71 GeV, which corresponds to a radiative return
to the Z.
Hence, the event features the production of a Z0 with both initial and
final state radiation.
Other radiative return :
e+ e- --> f fbar gamma :
- r080842e010444,
(q qbar) gamma
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Hadronic event coplanar with a hard photon of 61 GeV.
The missing vector is compatible with the emission of a second photon
of about 70 GeV in the beam pipe.
The hadronic system has a very low mass, about 14 GeV.