SWGuideDisplacedDimuonHLT < CMSPublic

---+!! Displaced Dimuon High Level Trigger
%COMPLETE4%

%TOC{title="Contents:"}%

---++ Trigger outline (preliminary)
   * events have to pass the L1 dimuon trigger
   * if you choose the L2 path, 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 opening angle of the two tracks

---++ Usage for <nop>CMSSW_1_3_0
   * tcshell:
<verbatim>
scramv1 project CMSSW CMSSW_1_3_0
cd CMSSW_1_3_0/src
eval `scramv1 run -csh`
project CMSSW
cvs co -r V00-03-04 RecoTracker/TkSeedGenerator
cd RecoTracker/TkSeedGenerator
scramv1 b
cd ../..
cvs co -r V00-00-35 HLTrigger/btau
cd HLTrigger/btau
scramv1 b
</verbatim>
   * modify =data/displacedmumu/PathBToJpsiToMumu.cff= and =test/hltBToJPsiToMumu.cfg=
   * with L2 muons modify =data/displacedmumu/PathBToJpsiToMumuWithL2.cff= and =test/hltBToJPsiToMumuWithL2.cfg=


---++ Usage for <nop>CMSSW_1_3_0_pre6
   * tcshell:
<verbatim>
scramv1 project CMSSW CMSSW_1_3_0_pre6
cd CMSSW_1_3_0_pre6/src
eval `scramv1 run -csh`
project CMSSW
cvs co -r V00-03-04 RecoTracker/TkSeedGenerator
cd RecoTracker/TkSeedGenerator
scramv1 b
cd ../..
cvs co -r V00-00-29 HLTrigger/btau
cd HLTrigger/btau
scramv1 b
</verbatim>
   * modify =data/displacedmumu/PathBToJpsiToMumu.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)
   * minimul cosine of the opening angle of the two muons (> 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)

---+++++!! Problem
   * use L1 muons as seeds: the have to be corrected for drift in magnetic field
   * this depends on charge which is not correctly assigned by L1 trigger
 
---++ Plans
   * try to use L2 dimuon filter
   * this would eliminate L1 muon charge problem
   * might improve timing

#ReviewStatus
---++!! Review Status

| *Editor/Reviewer* | *Comments* |
| Main.LotteWilke - 26 Mar 2007 | page author |
| Main.JennyWilliams - 27 Mar 2007 | edited to fit swguide general layout |

%RESPONSIBLE% Main.LotteWilke %BR%
%REVIEW% Reviewer

This topic: CMSPublic > CMSCommunicationsGroup > CMSCommunicationsProjects > WebHome > SWGuide > SWGuideOnSel > SWGuideTriggerStudiesHowTo > SWGuideDisplacedDimuonHLT
Topic revision: r4 - 2007-04-04 - unknown

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