Separation of γπ0 showers at high energies

We have designed and carried out simulation studies of a two-layer Shower Maximum Detector diagonally off-set (SMD-dos) optimized for the separation of π0 showers from γ showers in the 30–150 GeV energy range. For 90% γ acceptance the SMD-dos yields π0 rejection efficiencies of 92 ± 4%, 87 ± 4% and 32 ± 2%, respectively, for 30, 50 and 150 GeV incident energies. We find that the two-layer SMD-dos is superior to a conventional geometry two-layer Shower Maximum Detector (SMD), of equal granularity, by an average factor of ∼1.5 over the 50–150 GeV energy range. o find the interesting result that the two-layer SMD-dos is superior to a higher granularity one-layer SMD which uses the same number of channels. ron-hadron colliders the signature of choice for the detection of the Higgs particle, in the mass range of 120–160 GeV, is via the decay H → γγ. The addition of a SMD-dos to the planned detectors at the LHC would significantly reduce the background to the γ signal coming from prolific π0 production.