1. A. BHASIN ALICE offline Software Week 13th June 2002 Dimuon High Lelvel Trigger (DHLT) ● Goals ● FM Algorithm ● Proposal for a new Algorithm

2. A. BHASIN ALICE offline Software Week 13th June 2002 DIMUON SPECTROMETER

3. A. BHASIN ALICE offline Software Week 13th June 2002 Goals  Demonstrate that algorithm can achieve 5-6 rate reduction using only small fraction of event data(from station 4 & 5).  Implement this algorithm in AliRoot framework(should be extractable for implementation on hardware)  Provision to include other tracking stations, trigger chamber, other detectors(ITS) and study the efficiency.  Need to validate the algorithms for Dimuon physics plan, taking into account all possible backgrounds.

4. A. BHASIN ALICE offline Software Week 13th June 2002 FM Algorithm Muon Filter Dipole (xf,yf,zf)  Station 4 Station 5 T1 Y T2 (X,Y) T1 RsRs R PRO T2 Franck Manso’s algorithm – Filtering and uses the hit information from stations 4 & 5 to improve the p T resolution and hence the p T cut – Helps in reducing the background.

5. A. BHASIN ALICE offline Software Week 13th June 2002 Proposed Algorithm ● Hit finding in station 4 and 5 using the Raw Clusters (cog method). Make segments in each of these stations and calculate p T. ● Validate the track in Station 3. ● Provision for including other Stations(1 &2), Trigger chambers and other detectors for better track information.

6. A. BHASIN ALICE offline Software Week 13th June 2002 Implementation In AliRoot galice.root ReadHits( ) RawClustersSt45( ) FillEventHlt( ) HltDecission( ) AliMUONHlt Simple Clustering (C.O.G method) only deconvulate clusters AliMUON RawClusters AliMUONEventReconstructor SortHitsForRecInSt45( ) MakeSegmentsPerStation( ) MakeSegments45( ) MakeTracks( ) MaketrackCandidateswithTwosegments( ) MakeTrackCandidatewithoneSegmentationandonepoint( ) MakeTrackCandidatesSt45( ) RemoveDoubleTrack( ) FollowTracksinSt3usinghits( ) FollowTracksinst1&2usingLUT( ) GetBendingMomentumFromImpactParameter( ) AliMUONHlt :: RawClustersSt45( ) TreeR AliMUONHlt::FillEventHlt( ) MUONHlt TreeR