Displaced Dimuon High Level Trigger

Trigger outline (preliminary)

• events have to pass the L1 dimuon trigger
• L2 muons are reconstructed and filtered on
• primary vertex is reconstructed
• muon tracks are reconstructed using the L1/L2 muons as seeds
• two muon tracks are combined (to build e.g. a J/psi) and required to be within a certain mass range
• The Kalman Vertex Fitter is applied on these two tracks
• A cut is applied on the decay length singnificance, on the chi² of the fit and on the angle between the momentum of the two combined tracks and the decay length

Usage for CMSSW_1_3_1_HLT2

• tcshell:

scramv1 project CMSSW CMSSW_1_3_1_HLT2
cd CMSSW_1_3_1_HLT2/src
eval `scramv1 run -csh`
project CMSSW
cvs co -r V00-00-50 HLTrigger/btau
cd HLTrigger/btau
scramv1 b

• modify data/displacedmumu/PathBToJpsiToMumu.cff, data/displacedmumu/L3ForDisplacedMumuTrigger.cff and test/hltBToJPsiToMumu.cfg

What can be modified?

in included package HLTDisplacedmumuFilter

• minimal decay length significance (> 3)
• maximal normalised Chi2 of the Kalman Vertex Fitter (< 10)
• minimal cosine of the opening angle between the momentum of the two combined tracks and the decay length (> 0.9)

in CandSelector

• the transverse momentum of the muon (> 2.5GeV)

in CandCombiner

• the invariant mass (2.95 < m < 3.25) and momentum of the mumu particle(> 4GeV)

Review Status

Responsible: LotteWilke
Last reviewed by: Reviewer