L3 Muon Trigger at D0 Status Report Thomas Hebbeker for Martin Wegner, RWTH Aachen, April 2002

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L3 Muon Trigger at D0Status ReportThomas
Hebbeker for Martin Wegner, RWTH Aachen, April
2002

• The D0 muon system
• Functionality of the L3 muon trigger
• Muon efficiencies
• Muon rejection
• Summary and Outlook

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The D0 Muon system

• Central region (h1)
• 3 layers of drift tubes
• 1 layer inside, 2 layers outside the toroid
• 2 layers of scintillation counters
• Forward region (1lthlt2)
• 3 layers of Iarocci tubes
• 3 layers of trigger scintillators

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Functionality of the L3 trigger

Linux PC farm, adapted offline reconstruction
code, 45 ms per event
M.W.
M. G.
M.W.
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Input parameters

• track quality (below)
• transverse momentum
• detector region
• match with central track or calorimeter

Definitions of muon categories

• "Loose"
• 1 of the "tight" criteria failed
• no c2 requirement
• "A-stub"
• of scint. hits in A gt0
• of wire hits in A gt1

• "Tight"
• of scint. hits in A gt0
• of wire hits in A gt1
• of scint. hits in BC gt0
• of wire hits in BC gt2
• c2 of track gt0 (i.e. fit converged)

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A first glimpse geometrical coverage
Number of loose tracks

• Single m MC,
• flat from -2.5 to 2.5,
• pt flat from 2.5 to 200 GeV
• all loose tracks

• On a large scale loose tracks are uniformly
  distributed in h and j.
• Tracks are missing
• at octant boundaries in forward region
• in the bottom octants at transition from WAMUS to
  FAMUS

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Efficiencies for single muon MC

• Overall efficiencies
• 50 for "tight."
• 77 for "loose.
• 71 for "a-stubs."
• Eff. for tight muons and A-stubs are correlated.

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Data the "Moriond samples"

• Sample of 1894 selected Di-Muon events in FAMUS
• In 84 of the events at least one a-stub was
  found by the trigger
• " 82 " " " at least two a-stubs
  were found
• " 83 " " " at least one loose
  muons were found
• " 81 " " " at least two loose
  muons were found
• " 78 " " " at least one tight
  muon was found
• " 46 " " " at least two tight
  muons were found

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Rejection factors over L1

• Data special run with L1 trigger mu1ptxctxx
  only
• 19324 events
• Without pt cut the rejection factor is 1.88 for
  loose and 4.1 for tight muon tracks

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The next steps
Summary current status

• L3 muon trigger works in principle
• Efficiencies too low

• Fix memory leak.
• Event by event comparison of L3 results and
  offline reconstruction.
• Improve efficiency. Problem in unpacker ?
• Implement cross-octant segments etc.
• Build relational filters for physics.