PileUp Framework Concept

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Pile-Up Framework Concept
Paolo Calafiura, LBL

• Software Workshop
• May 14, 2001

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Pile-up Framework tasks

• read events from multiple streams (physics, min
  bias...)
• organize them in time ordered structures (the
  bunch crossings)
• combine hit collections from the sub-events in
  the Xing, merging nearby hits according to
  detector-specific criteria

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Pile-Up Entities

• Event Stream
• input physics event input iterator drives
  event loop
• input min bias random access iterator (and
  Muon bkg and LAr?)
• output overlaid events
• Bunch Crossing
• time-ordered collection of sub-events
• time offset identifies sub-events
• configure duration, contributing streams
  evts/stream, event offset distributions
  (Poisson, but also uniform and delta-function)

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Bunch Crossing Object Diagram
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Overlaid EventInfo
collisions
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Pile-Up Entities contd

• Hit (and digi) collections
• input collections get copied into overlaid event
• hits in overlaid collection carry parent
  sub-event(s?) offset(s?)
• Hit (and digi) mergers
• detector specific (sub-)algorithms
• sort hits in time and space
• merge nearby hits

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Hit Merging