The positron momentum is measured to be 37.1 GeV/c in the tracking chambers and has an associated energy in the HPC of 30.0 GeV. It has no (or little) energy deposited in the HAB and is a clearly identified positron.
The Mu- has a 25.4 GeV/c momentum. It is not observed in the HPC and is minimum ionizing in the HAB. It has associated hits in both planes of the barrel muon chambers. It is a clear muon.
There is about 30 GeV energy missing in the event, which is carried away by the neutrinos.