DELPHI Z0 PEAK EVENT

DELPHI Event r0033964e0002962


e+ e- ---> q qbar gamma gamma , 2 muons
Two jets and two hard gammas are clearly seen. The gamma showers are seen in the HPC with 31.4 and 28.2 GeV energy. They are well separated from the jets, the minimum angle of a gamma with a jet being about 50 degree. Their effective mass is 56.7 +- 1.6 GeV and their recoil mass 26.1 +- 2 GeV. In both jets, one particle is identified as Mu+. One Mu+ has 2.6 GeV/c, is MIP in HPC and HAB and has hits associated in both planes of the MUB. The other Mu+ has 2.0 GeV/c, is not detected in HPC, is MIP in the HAB and has a hit associated in the inner layer of the MUB.

Ref : Presented by U.Amaldi after the seminar of S.C.C.Ting (CERN, 26 Nov 1992) on high mass photon pairs.