Photon Reconstruction 07/16/2012

Problem

Even after timing cuts, still have large background under pi0 peak.

Splitoffs?

• Splitoff suppression in Crystal Barrel, CLEO
  • Various discriminators to distinguish between splitoffs, photons
    • Distance/angle between potential parent cluster and potential splitoff
    • Energies of parent and splitoff
    • E9/E25
    • Left-right/up-down asymmetry
  • Feed this into a neural net to determine splitoff probability
  • Alternate FCAL clustering to minimize splitting of hadronic showers (naive algorithm just to group together neighboring hits)

What's next

Better understand origin of these extra clusters.