1. BEACH Conference 2006 Leah Welty Indiana University BEACH 2006 7/7/06

2. BEACH Conference 2006 Outline : Movin’ On In Tevatron D0 Detector - unwrap it onion style Tracking improvements Trigger discussion Conclusions

3. BEACH Conference 2006 Fermilab

4. BEACH Conference 2006 Fermilab DZERO

5. BEACH Conference 2006 D-Zero : Detector Muon Detectors Calorimeter Central Fiber Tracker Silicon Detector NEW Layer 0  =0  =1  =2  =3

6. BEACH Conference 2006 D-Zero : Muon Detectors Tracking Detectors –Drift Tubes (Mini & Proportional) –Fine segmentation –Slow readout Trigger Detectors –3 layers scintillators –Course segmentation –Fast readout Muon Toroid –Allows for stand alone momentum measurement Source of much of our power

7. BEACH Conference 2006 D-Zero : Muon Detectors Cosmic ray rejections –Scintilator timing Very low punch through –14 interaction lengths –Have to get through toroid Solenoid & Toroid –Polarities reversed roughly every week –4 combinations of S&T combinations exposed to ~equal integrated luminosity –Good for systematic studies Triggered and reconstructed Muons (semileptonic b decay) Large |  | coverage! Very Beneficial

8. BEACH Conference 2006 CP Violation of B 0 mixing and decay result Took advantage : –solenoid and toroid reversals –Muon trackers and triggers Reducing cosmics Large  coverage Resulting in a world’s best measurement Muon Detectors in Action

9. BEACH Conference 2006 D-Zero : Calorimeter

10. BEACH Conference 2006 D-Zero : Calorimeter Designed for high p T physics Help in B-Physics? “Road Electrons” - Energy associated with central track p T >2 GeV “Calorimeter Muons” - MIP in calorimeter for  ID ~10% increase in signal J/   D 2 (  )=1.48%  D 2 (e - )=0.21% Tagging preformance

11. BEACH Conference 2006 D-Zero : Trackers

12. BEACH Conference 2006 D-Zero : Fiber Tracker Radius : 20cm - 52cm Fibers used for best resolution for our tracking volume Covers central pseudo rapidity region |  |<2 Reconstruct tracks + measure momentum of charged particles

13. BEACH Conference 2006 D-Zero : SMT 6 Central Barrels –8 Layers of Ladders –Inner 4 barrels All double-sided for 3D reconstruction –Outer 2 barrels Half of the layers double-sided 12 Central ‘F’ Disks –Double-sided –Radius : 2.6cm -10.0cm 4 Forward ‘H’ Disks –Single-sided –Radius : 9.5cm - 26cm –Tracking out to ~  =3

14. BEACH Conference 2006 D-Zero : Layer 0 Fits around the beam pipe and inside current silicon detector Radius : 16mm Beam Pipe Provide more robust tracking power and help with pattern recognition at higher luminosities ~6/21/06 Installed over shutdown (~2/23/06 ~ 6/4/06)

15. BEACH Conference 2006 Tracking in Action B s lifetime result Importance still on the muon detector Takes advantage of tracking also –Signed decay length –Primary & decay vertex Resulting in a world’s best measurement

16. BEACH Conference 2006 Tracking Corrections Motivation –The masses of many particles at D0 were being measured, however they were slightly off of the PDG value. –To combat this problem we looked at two sources: Missing material in our reconstruction code Variations in the magnetic field

17. BEACH Conference 2006 Tracking Corrections Used a Bethe-Bloch inspired correction to account for missing material Used simple scale factor to take care of extra difference (B-Field Correction)

18. BEACH Conference 2006 Before & After UNCORR CORR Uncorrected the mean of the narrow peak is 3.075 GeV Corrected the mean of the narrow peak is 3.098 GeV Splitting between the narrow and wide Gaussian means is less after corrections. M(J/  ) PDG =3.097 GeV Mean1=3.075 Mean2=3.065 Mean1=3.098 Mean2=3.093

19. BEACH Conference 2006 Before & After Before the corrections the p T distribution of the M(J/  ) has a large dependence. After corrections applied M(J/  ) is much flatter and distributed around the PDG value of the J/  mass.

20. BEACH Conference 2006 Trigger System p p Crossing Frequency 1.7 MHz Data Acquisition rate limited to average 55Hz (up to 150Hz) 3 Level Trigger System 4.2  s100  s 50 ms L1 L2 L3 1.7 MHz 2.5 kHz1 kHz 150 Hz Hardware based Simple decisions Software + Firmware Physics Objects e, ,jets,tracks Software based Simple versions of recon. algorithms ( Hz) Inelastic xsection:60mb D + ~4.2  b & B + ~3.6  b

21. BEACH Conference 2006 Trigger System 4.2  s L1 1.7 MHz Hardware based Simple decisions Muon + EM + Jets completely fills up L1 NO ROOM for “track only” trigger D-Zero’s B physics program is therefore muon based This is the major difference between D0 and CDF in the B-physics programs Our superhero muon detector comes to the rescue!

22. BEACH Conference 2006 CAL FPS CPS CFT SMT Muon L1 Muon L1CTT L1CALL2CAL L2PS L2CFT L2STT L2 Muon Global L2 DetectorL1 TriggerL2 Trigger L1 Framework Towers, tracks, correlations L2 Framework Combined objects E,mu,jets L3 F A R M (track trigger) (muon trigger) (IP Trigger)

23. BEACH Conference 2006 Di-Muon Triggers Low Luminosity –Muon system only trigger –Both muons |  |<2 –1st muon Required to hit all layers –p T >3 –2nd muon One layer –p T >1.5 High Luminosity –1st muon p T >3 in central region |  |<1.5 Central track match –2nd muon All layers –p T >3

24. BEACH Conference 2006 Single Muon Triggers Low Luminosity –|  | 3 GeV Muon + Trk match at Level 1 & muon at Level 2 Unbiased –No IP cuts Turned off >60-100e30 Medium –Extra tracks High Luminosity –Impact Parameter requirements –Associated invariant mass –Track selections at Level 3

25. BEACH Conference 2006 Level 3 Fast track reconstruction High efficiency wrt recon Down to p T >0.5 |  |<1.5 Primary vertex & I.P. reconstruction 2 tracks –pT>1.5 –IP sig>3 Cuts on invariant mass , D s # tracks >pT cut # IP tracks Invariant mass Use all possible combinations to reject or keep event Tuned on semileptonic B s data

26. BEACH Conference 2006 Trigger Plots L1 Rate vs Luminosity Phi Mass at L3 Efficiency vs Rejection L3

27. BEACH Conference 2006 In the Life of Muon Triggers ~200-300E30 –p T >5-6 150-200E30 –pT>4-5 100-150E30 –pT>3 GeV –Tight L3 <100E30 –pT>3GeV –Loose L3 ~30 Hours

28. BEACH Conference 2006 Conclusions Strongest D0 detector component for B-physics is our muon detector –Although can use all parts (Calorimeter + tracking) to aid in several other analysis D-Zero has a strong B physics program –9 publications on Run2a data –3 currently submitted –14 preliminary results Rely on the detector & writing triggers which allow us to get the most out of the data flow. –Quick turnaround for analysis Presented B s mixing results a few months after data taking ended on a full 1 fb -1 data sample