1. A. Zoccoli - PRC open session 16-May-2002 HERA-B A. Zoccoli Università and INFN - Bologna PRC open session 16 th May 2002

2. A. Zoccoli - PRC open session 16-May-2002 Outline  Status of the 2000 data analysis  Detector and trigger:  present status  results of 2001 data analysis  2002/3 Physics program  Summary

3. A. Zoccoli - PRC open session 16-May-2002 Run 2000 Analysis Topics Statistics  Minimum Bias: 2 million events (C, Al, Ti, W targets)  DiLepton trigger: 0.45 million events DI-  0.90 million events DI-e Minimum bias no trigger  K s 0 &  production cross section.  Inclusive particle productions.   polarization Trigger Topic Lepton pair: e + e - ECAL pretrig     Muon pretrig + SLT tracking  bb production cross section  Fraction of J/  from  c  Inclusive J/  x f & p t distributions  J/  production cross section  IR ~ 5 MHz

4. A. Zoccoli - PRC open session 16-May-2002 Minimum Bias: V 0 production V 0 Cross section K0K0 00 K 0 s &  mass distr. K 0 s &  nuclear dependence K0K0 00 00

5. A. Zoccoli - PRC open session 16-May-2002 Dilepton trig. : Prompt J/  (Muon) PID:  likelihood from MUON detector and RICH Trigger tracks confirmed by reconstruction Xf:Xf:p t :

6. A. Zoccoli - PRC open session 16-May-2002 Dilepton trig. : Prompt J/  (Electron) Particle ID: E/P + bremsstrahlung Trigger tracks confirmed by reconstruction: Total number of J/  in the sample: n P = 5710  380 ST  280 SYS  BR =0.34  0.02  0.02

7. A. Zoccoli - PRC open session 16-May-2002 In 2002: - First measurement of  c suppression in nuclear matter. - Study of production ratios between J /  c and  ‘. - Disentangle the 2  c states (?) Fraction of J/  from  c  c  J/   M=M(J/  )-M(J/  ) (GeV/c 2 ) Entries / 25 MeV/c 2 ee  C C Ti All  Preliminary results: R  c =  (Carbon) R  c =  (Titanium) In agreement with previous p-N experiments.

8. A. Zoccoli - PRC open session 16-May-2002 The HERA-B  (bb) Measurement Principle of the measurement: b  J/  X   +  - X b  J/  X  e + e - X Look at the chain: via detached J/  vertices. l + J/  B zz X l - IWIW upstream | downstream Normalization on the inclusive prompt J/  cross section.  Systematic error minimization

9. A. Zoccoli - PRC open session 16-May-2002 The Muon Channel: b-cuts UNBINNED LIKELIHOOD FIT (due to low statistics): - Sig. shape from MC, - BKG shape from data. Mass spectrum upstream and downstream: Cuts applied:  z > 7.5  z   Imp. Param. to wire I w > 35  m   Imp. Param. to primary vtx I p > 160  m Optimization procedure:  +  - invariant mass ( GeV/c 2 ) Entries / 100 MeV/c 2

10. A. Zoccoli - PRC open session 16-May-2002 The Electron Channel: b-cuts UNBINNED LIKELIHOOD FIT (due to low statistics): - Sig. shape from MC, - BKG shape from data. Cuts applied:  z > 0.5 cm e  Imp. Param. wire I w > 200  m, or Min. dist. @ Z W to any other track > 250  m Optimization procedure: Mass spectrum upstream and downstream: e + e - invariant mass ( GeV/c 2 ) Entries / 100 MeV/c 2

11. A. Zoccoli - PRC open session 16-May-2002  (bb) Determination  Simultaneous fit to e + e - &  +  - (in acceptance): QCD calculations and experimental results: Extrapolation to the Hera-B acceptance: 5.7  1.5  1.3 nb/nucl.E789: nb/nucl. E771:  TOT (bb) = nb/nucleon

12. A. Zoccoli - PRC open session 16-May-2002 Summary of 2000 analysis The analyses on Dilepton and Minimum Bias data taken during the 2000 run are well advanced.  Understanding of the detector, of the efficiencies, of the performances, etc.  Preparation of the analysis codes in view of the 2002/3 run.  Papers on bb cross section (almost final), production of J/  from  c, V 0 production cross section and J/  decay spectra are in preparation.

13. A. Zoccoli - PRC open session 16-May-2002 2002/3 Detector Configuration Thinner beam pipe: 500  m  300  m No magnet tracker! Motivation to reduce material: - Improve calorimeter performance. e.g. 1.5x better resolution on (  c - J/  ) mass difference - Influence on tracking shown to be small at 5 - 10 MHz interaction rate. - (being kept in a safe place in case of possible future use)

14. A. Zoccoli - PRC open session 16-May-2002 Status & actions during the shutdown VDS Fully operational in 2000. Detector modules repaired. ITR Installation of missing chambers. Dead chambers repaired. Noise reduction (improved grounding). OTR Dead HV groups repaired and HV stability improved Noise reduction  Higher efficiency expected. RICH Fully operational in 2000. ECAL Reduction of common noise (grounding improved)  better E resolution. MUON Dead channels repaired. Noise reduction  higher efficiency expected.  The HERA-B detector was operational in 2000 run.  Many improvements during the shutdown.  Partially checked in the short run end of 2001. Status of detector components New improved grounding scheme on all chambers:  reduction of pick-up  lower fluctuation of raw data Old New ADC counts Before magnet After magnet Itr in 2002 Stations Width of Raw Data [ADC] ~ 3% of dead channels vs ~15% in 2000. Effect of Dead HV groups Repair, geometrical efficiency: Noise reduction  Higher efficiency expected To be measured in the near future Old Threshold Otr in 2002 100 90 ADC pedestals in the new ECAL run configuration:  Better performances in PId To be measuerd in the near future Ecal noise situation December 2001 2000 Run

15. A. Zoccoli - PRC open session 16-May-2002 Status of First Level Trigger The First Level trigger was not fully commissioned in 2000. Low efficiency due to both trigger and detector performances. Main activities:  Optical Links: despite large effort, will remain the most critical HW item  Flt Algorithm fully optimized.  Processor logic fully verified (vector test).  Detector mapping ready, verification in progress  Online software improved system  New RICH multiplicity veto system available Waiting for data to check the performance !

16. A. Zoccoli - PRC open session 16-May-2002 December 2001 data Minimum Bias (int. Trig.): ~500k events only ~10 hours RUN ! Charged tracks Checks on reconstruction and alignment, comparison with 2000 data: K0K0 00 Inclusive distributions K 0 s &  mass distr. 2000 2001 K S width already smaller than in 2000!

17. A. Zoccoli - PRC open session 16-May-2002 December 2001 data - II More data welcome ! Neutrals Checks on reconstruction and calibration: InnerMiddleOuter   0 seen in the Outer. After one calibration iteration (out of three). Width very close to that of 2000.

18. A. Zoccoli - PRC open session 16-May-2002 2002/3 Physics Program Base line physics program for next run: A) Detailed measurement of atomic number dependence of charmonium production - Extend existing measurements of J/  and  ’ to negative x F. - First measurement of atomic number dependence of  c. B) Improved bb cross section measurement -Systematics limit at  15% (normalization). - Cross section from full reconstructed B mesons

19. A. Zoccoli - PRC open session 16-May-2002 Additional topics: - Charmonium spectroscopy – Drell-Yan - Measurement of  production - Open charm production - Strangeness production in nuclear matter -  polarization Expected event yields: 2002/3 2000 J/  (  & e )   ~4 10 6 ~1 10 4  c  J/  ~3 10 5 ~1 10 2  ´  ~1 10 5 ~4 10 1 Targets: primarily C, W (but also installedTi, Al & Pd) Acceptance in the range -0.4 < x f < 0.3 2002/3 Physics Program – II

20. A. Zoccoli - PRC open session 16-May-2002 Summary  The analysis of 2000 data is approaching completion.  Improved performance of the HERA-B spectrometer and understanding of the trigger.  first data look promising  trigger ready to be tested  Physics program: very large statistics of charmonium states expected in the next run.

21. A. Zoccoli - PRC open session 16-May-2002 Summary HERA-B is anxiously waiting for new data to come.

22. A. Zoccoli - PRC open session 16-May-2002

23. Systematic checks (e-channel) DECAY LENGTH LIKELIHOOD FIT: MC =0.81  0.03 cm RD =1.00  0.30 cm BKG =0.36  0.13 cm Different background optimisation: Upstream Downstream Dz (cm) Mass (ee) (GeV/c 2 ) Bkg

24. A. Zoccoli - PRC open session 16-May-2002 Status & actions during the shutdown VDS Fully operational in 2000. Detector modules repaired. ITR Installation of missing chambers. Dead chambers repaired. Noise reduction (improved grounding). OTR Dead HV groups repaired. Noise reduction  Higher efficiency due to lower threshold cut. RICH Fully operational in 2000. ECAL Reduction of common noise (grounding improved)  better E resolution. MUON Dead channels repaired. Noise reduction  lower threshold, higher efficiency.  The HERA-B detector was operational in 2000 run.  Many improvements during the shutdown.  Partially checked in the short run end of 2001. Status of detector components

25. A. Zoccoli - PRC open session 16-May-2002 New improved grounding scheme on all chambers:  reduction of pick-up  lower fluctuation of raw data Old New ADC counts Before magnet After magnet Itr in 2002 Stations Width of Raw Data [ADC]

26. A. Zoccoli - PRC open session 16-May-2002 ~ 3% of dead channels vs ~15% in 2000. Effect of Dead HV groups Repair, geometrical efficiency: Noise reduction  Higher efficiency expected To be measured in the near future Old Threshold Otr in 2002 100 90

27. A. Zoccoli - PRC open session 16-May-2002 ADC pedestals in the new ECAL run configuration:  Better performances in PId To be measuerd in the near future Ecal noise situation December 2001 2000 Run