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T1 performances

T1 performances. Update on the work in progress. At the end of September…. Multiplicity Occupancy Trigger rates Ghost rejection Pattern recognition Track reconstruction Vertex reconstruction Momentum reconstruction (?). Geometric efficiency (after revision). Occupancy.

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T1 performances

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  1. T1 performances Update on the work in progress Fabrizio Ferro

  2. At the end of September… • Multiplicity • Occupancy • Trigger rates • Ghost rejection • Pattern recognition • Track reconstruction • Vertex reconstruction • Momentum reconstruction (?) Fabrizio Ferro

  3. Geometric efficiency (after revision) Fabrizio Ferro

  4. Occupancy Avg rate per event • Final geometry revision in the simulation  occupancy update Wires N wire Strips N strip Fabrizio Ferro

  5. Hit reconstruction Simplified digitization 3 coordinates per CSC REC. Hits From residuals: sx ~ sy ~ 0.7 mm mm mm SimHits  RecHits Fabrizio Ferro

  6. Ghosts rejection REC hits vs SIM hits ratio SD NSD T1 one arm Empty for this arm-non empty for other arm or T2 One sextant Fabrizio Ferro

  7. Two events: visualization of one arm y y Pri hits Sec hits Eta Rec hits x x Eta Phi Phi Fabrizio Ferro

  8. Reconstruction: pattern recognition Algorithm for the grouping of hits in one arm using their projection onto a h,f plane to identify pointing tracks candidates (regions of interest) Roads A road is a cone where at least 4 hits in 4 different planes are found. Cone parameters to be optimized. Chosen: Df=0.1 Dh=0.2 Fabrizio Ferro

  9. Road selection: cuts selected GeV Dh and Df in primary tracks (1st -5th plane) cut cut Dh Df The road finding algorithm cuts primary tracks with low pT Fabrizio Ferro

  10. Two events: visualization of one arm y y Pri hits Sec hits Rec hits Roads x x Eta Eta Phi Phi Fabrizio Ferro

  11. Road selection: results At least one road in ~ 93% (96%)* of non empty SD events. At least one primary road in ~96% (98%)* of SD with primaries in T1 At least one road in ~ 99% of non empty NSD events. At least one primary road in ~99% of NSD with primaries in T1 * No B field SimHits  RecHits  Roads Fabrizio Ferro

  12. Track fitting • Roads with >3 points and <10 are sent to the fitting routine • All combinatorials with a hit in 4 or 5 planes are fitted with straight lines in both projections (xz and yz) • Fit output is the track with minimum (c2xz + c2yz)/2 SimHits  RecHits  Roads  Straight tracks Fabrizio Ferro

  13. Vertexing • Tracks with both c2xz and c2yz > c2cut are discarded (bad fit in both projections) • Vertex candidate: average of the points of minimum approach ( zv = Szi/Ntr ) • Iteration procedure if more than 2 tracks involved: the furthest track from zv is discarded if |zi-zv|>Dcut (Dcut = 10 cm, to be optimized) • Iteration stops if |zi-zv|<Dcut i or Ntr=2 SimHits  RecHits  Roads  Straight tracks  Vertex Fabrizio Ferro

  14. Preliminary results • Single diffraction • with B: zRMS ~ 29cm xRMS ~ 1.9cm • without B: zRMS ~ 12cm xRMS ~ 1.3cm • Minimum bias + double diffraction • with B: zRMS ~ 18.7cm xRMS ~ 1.7cm • without B: zRMS ~ 8.2cm xRMS ~ 1.3cm Fabrizio Ferro

  15. Vertex distributions (z) SD NSD s1=13.8cm s2=38.7cm B s1=3.7cm s2=18.1cm B s1=4.7mm s2=5.7cm s1=3.8cm s2=13.1cm no B no B Fabrizio Ferro

  16. Vertex distributions (x) SD NSD s=1.3cm B s1=3.6mm s2=15mm B s=6.6mm s1=2.9mm s2=9.4mm no B no B Fabrizio Ferro

  17. Number of reconstructed events • Single diffraction (egeo ~ 68%) • with B: ~65% • without B: ~67% • Minimum bias + double diffraction (egeo ~ 97%) • with B: ~97% • without B: ~97% Fabrizio Ferro

  18. Beamgas p z • The road reconstruction behaves as a cut on the angle of tracks. This naturally rejects tracks coming from a vertex far from the nominal interaction point. • BG at 10m: no vertices • BG at 5m: ~2% • BG at 2m: ~50% • BG at 0: ~60% • BG at -2m: ~60% • BG at -5m: ~50% • BG at -10m: ~40% Fabrizio Ferro

  19. Beamgas • Two examples Beamgas at 2m Beamgas at -5m Fabrizio Ferro

  20. To do… Ghosts: check digitization and introduce “random” background Pattern recognition: cuts optimization and (maybe) isolation cut on road Vertex reconstruction: better understanding of vertexing algorithm Trigger pattern: finalize studies Simulation of background (“empty”) events to be investigated – help needed Fabrizio Ferro

  21. Summary • Multiplicity • Occupancy • Trigger rates • Ghost rejection • Pattern recognition • Track reconstruction • Vertex reconstruction • Momentum reconstruction (?) • Multiplicity • Occupancy • Trigger rates • Ghost rejection • Pattern recognition • Track reconstruction • Vertex reconstruction • Momentum reconstruction (?) Fabrizio Ferro

  22. Fabrizio Ferro

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