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Muon Trigger and Physical Processes with Hard Muons at a Collider Experiment

Muon Trigger and Physical Processes with Hard Muons at a Collider Experiment. V. Palichik Joint Institute for Nuclear Research Dubna. NEC’2003 Varna, Bulgaria 15 September, 2003. Study of Processes with Hard Muons. 2007: start of 14 TeV LHC

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Muon Trigger and Physical Processes with Hard Muons at a Collider Experiment

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  1. Muon Trigger and Physical Processes with Hard Muons at a Collider Experiment V. Palichik Joint Institute for Nuclear Research Dubna NEC’2003 Varna, Bulgaria 15 September, 2003

  2. Study of Processes with Hard Muons 2007: start of 14 TeV LHC An interest to search heavy resonances (Z, W, gkk) in TeV region: C.-E.Wulz “Z at LHC”,CMS-TN/93-107. P.Traczyk, G.Wrochna “Search for Randall-Sundrum Gravition Excitations in the CMS Experiment”, CMS Note 2002/003. C.Alexa “Prospects for Exotic Physics at the LHC”,ATL-CONF-2001-005. D.R.Tovey “Searches for New Physics at the LHC”, ATL-CONF-2002-005. I.Golutvin, P.Moissenz, V.Palichik, M.Savina, S.Shmatov “Search for TeV-scale bosons in the +- decay channel in CMS”,reported at Conf. ”Physics at LHC”, Prague, July, 2003. V. Palichik NEC’2003 Varna, Bulgaria 15 September, 2003

  3. An eхаmple of di-muon event(Pt of muons ~ 1 TeV) V. Palichik NEC’2003 Varna, Bulgaria 15 September, 2003

  4. Identification and reconstruction of TeV muons on L1 and L2 trigger levels L1 reconstruction of TeV muons in CSCs: N events Pt (L1) Pt, GeV V. Palichik NEC’2003 Varna, Bulgaria 15 September, 2003

  5. The principle of working of a Cathode Strip Chamber V. Palichik NEC’2003 Varna, Bulgaria 15 September, 2003

  6. Cathode Local Charge Track (CLCT) in CSC N layer ADC 1/2–strip algorithm on 6 layers 1 2 3 CLCT RMS accuracy of 0.15 strip width 4 5 6 N strip V. Palichik NEC’2003 Varna, Bulgaria 15 September, 2003

  7. Level-2 Algorithm for Muon Reconstruction • L1 muon trigger data provides (eta-phi)-region for muon track searching; • track-segments building in a given (eta-phi)-region for each chamber; • L2 trajectory seeding (position and momentum) on a base of L1 muon tracks; • track reconstruction using Kalman filter technique. V. Palichik NEC’2003 Varna, Bulgaria 15 September, 2003

  8. An example of L1&L2 reconstruction of a simulated 1 TeV muon event in CSCs r,cm Standard object-oriented reconstruction generated muon rz - projection Pt(gen)=1000 GeV * CLCTs L1 reconstruction Z, cm j,rad Pt(L1)= 6 GeV s CSC hits j z - projection CSC track segments m CSC hits used for L2 reco Kalman filter propagation states + L2 reconstruction Pt(L2)= 5 GeV Z, cm Drawn by Ivan Belotelov, JINR V. Palichik NEC’2003 Varna, Bulgaria 15 September, 2003

  9. Reconstructed Pt (L2) distribution for 1 TeV muons Standard object-oriented reconstruction Pt, GeV Pt, GeV The results obtained in cooperation with Ivan Belotelov V. Palichik NEC’2003 Varna, Bulgaria 15 September, 2003

  10. Modification of L2 reconstruction algorithm for TeV muons in CSCs • The algorithm of track segment building has been improved with taking into account the contamination of muon measurements by a secondary electromagnetic accompaniment. • New L2 trajectory seeding on a base of the best track-segment selection (on c2 criteria) in a wide L1 (h,j)-region has been proposed. The modifications of the algorithm have been created in cooperation with Ivan Belotelov V. Palichik NEC’2003 Varna, Bulgaria 15 September, 2003

  11. An example of L1&L2 reconstruction of a simulated 1 TeV muon event in CSCs r,cm Modified object-oriented reconstruction generated muon rz - projection Pt(gen)=1000 GeV * CLCTs L1 reconstruction Z, cm Pt(L1)= 6 GeV j,rad s CSC hits j z - projection CSC track segments m CSC hits used for L2 reco Kalman filter propagation states + L2 reconstruction Pt(L2)= 1300 GeV Z, cm Drawn by Ivan Belotelov, JINR V. Palichik NEC’2003 Varna, Bulgaria 15 September, 2003

  12. Reconstructed Pt (L2) distribution for 1 TeV muons Modified object-oriented reconstruction Pt, GeV Pt, GeV The results obtained in cooperation with Ivan Belotelov V. Palichik NEC’2003 Varna, Bulgaria 15 September, 2003

  13. pTof reconstructed muons in CMS tracking system dPt/Pt distributions barrel and endcaps ||  2.1 Z (500) Z (1200) red lines are muon pT distributions generated by PYTHIA blue lines are reconstructed ones fitted by Gauss V. Palichik NEC’2003 Varna, Bulgaria 15 September, 2003

  14. Z mass reconstruction in CMS Invariant mass of muon pairs from Pythia Full reconstruction of invariant mass Z (500) Z (1200) V. Palichik NEC’2003 Varna, Bulgaria 15 September, 2003

  15. Summary • A transverse momentum of TeV muons at L2 trigger level is significantly underestimated due to a hard contamination of muon measurements by a secondary electromagnetic accompaniment. • Tuned track segment building and new L2 trajectory seeding algorithm on a base of the best track-segments has been proposed. It essentially improves L2 Pt reconstruction in muon system for TeV muons. • Mass resolution of 5-6% for new gauge boson resonances Z (500) and Z (1200) in CMS has been obtained (with a natural width of 2-3%). V. Palichik NEC’2003 Varna, Bulgaria 15 September, 2003

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