DELPHI Z0 PEAK EVENT

DELPHI Event r0022854e0001782


e+ e- ---> gamma gamma gamma Mu+ Mu- (?)
Event with 3 gamma, two seen in the HPC (34.5 and 11.0 GeV), one in the EMF (39.75 GeV).

In addition, two slow opposite sign tracks are observed in the forward direction (0.54 positive, 0.92 GeV/c negative). The 0.92 GeV/c track is MIP in the EMF and HAF, hence its identification as an electron is excluded. It could be a muon, but there are no hits in the MUF (ranging out?). The other track leaves no energy in either calorimeter.

There is no clear interpretation for this event, but it could be a 3 gamma event with 2 muons (or pions).

Note : the tracks were reconstructed "by hand" and exist as TS, not as TK in TANAGRA.