1. Status of ZEUS Rainer Mankel DESY Hamburg --for the ZEUS collaboration-- PRC Public Session 26-May-2005

2. 26-May-2005R. Mankel: Status of ZEUS2 Outline Data-taking & detector status Data-taking & detector status Data processing & simulation Data processing & simulation Physics highlights Physics highlights heavy flavours heavy flavours QCD fits &  s determination QCD fits &  s determination diffractive final states diffractive final states

3. 26-May-2005R. Mankel: Status of ZEUS3 HERA-II Luminosity HERA-II finally at cruising speed almost reached integrated luminosity of HERA-I Instantaneous luminosity in e – p running surpassed e + p

4. 26-May-2005R. Mankel: Status of ZEUS4 ZEUS Data-Taking Series of daily gated luminosity records (  1.2 pb -1 ) Series of daily gated luminosity records (  1.2 pb -1 ) Remarkable improvement in ZEUS data-taking efficiency Remarkable improvement in ZEUS data-taking efficiency in general above 80% in general above 80% MVD on 95% of time MVD on 95% of time  62 pb -1 of new e – p data on tape [nb -1 ]

5. 26-May-2005R. Mankel: Status of ZEUS5 Detector Status Calorimeter: stable with low number of bad channels Calorimeter: stable with low number of bad channels MVD: signal & noise are stable MVD: signal & noise are stable CTD: low trip rate. No signs of premature ageing CTD: low trip rate. No signs of premature ageing Increased use of Global Track Trigger at global SLT level Increased use of Global Track Trigger at global SLT level  Detector is in good shape Efficiency improvements: Efficiency improvements: comprehensive monitoring via web statistics pages comprehensive monitoring via web statistics pages pre-luminosity test trigger runs pre-luminosity test trigger runs complete rebuild of TLT farm hardware & software complete rebuild of TLT farm hardware & software

6. 26-May-2005R. Mankel: Status of ZEUS6 Straw Tube Tracker (STT) STT presently off because of insufficient cooling, which otherwise interferes with stable operation of solenoid  Preparing repair that does not break beam vacuum additional cooling & insulation  Decision within next weeks FDET/STT add insulation & cooling GO magnet

7. 26-May-2005R. Mankel: Status of ZEUS7 Data Processing Central reconstruction & analysis facility for ZEUS Central reconstruction & analysis facility for ZEUS Presently farm of 150 Intel Xeon processors Presently farm of 150 Intel Xeon processors >600 000 analysis batch jobs in one year >600 000 analysis batch jobs in one year Up to 22000 jobs per week Up to 22000 jobs per week Average data throughput 10 TB/day Average data throughput 10 TB/day

8. 26-May-2005R. Mankel: Status of ZEUS8 ZEUS Reconstruction Performance Daily production (#events) during reprocessing of 2004 e + data: Daily production (#events) during reprocessing of 2004 e + data: 17-Oct9-Nov Date 1 M 2 M 3 M Events reconstructed per day Peak production: 3 M events/day Peak production: 3 M events/day at HERA-I times, peak rate was 500 k events/day at HERA-I times, peak rate was 500 k events/day reconstruction of HERA-II events is 6x more CPU- intensive than with HERA-I reconstruction of HERA-II events is 6x more CPU- intensive than with HERA-I  Sizable increase in processing performance  Fast turnaround 3 M events/day

9. 26-May-2005R. Mankel: Status of ZEUS9 HERA-II MC Production Assessment of Monte Carlo simulation needs in 2003 revealed opening of a huge gap Assessment of Monte Carlo simulation needs in 2003 revealed opening of a huge gap Reasons: Reasons: HERA-II luminosity HERA-II luminosity additional demand from new detector components additional demand from new detector components  considerable increase in simulation demand during HERA-II  Solution: Computing Grid Technology Gap

10. 26-May-2005R. Mankel: Status of ZEUS10 Solution: ZEUS Grid UI RLS dCache MSS SE RB WN CE SE WN CE DESY Zeus Integrated MC Production System Padova Tel Aviv Rutherford KEK Classical funnel sites GRIDGATEWAY Built on top of LHC Computing Grid software Built on top of LHC Computing Grid software Transparent integration of traditional funnel sites and grid sites Transparent integration of traditional funnel sites and grid sites Reuse of existing ZEUS- specific middleware Reuse of existing ZEUS- specific middleware “ZEUS Grid Toolkit” “ZEUS Grid Toolkit”  Brings the grid to the end user SE WN CE

11. 26-May-2005R. Mankel: Status of ZEUS11 ZEUS Grid-Based MC Production Totals  more than 200 million events produced  29 grid sites in 7 countries on 2 continents  >60% of MC produced on grid by time of last PRC: 600,000 events by time of last PRC: 600,000 events first non-LCG2 site: Univ. Wisconsin (joined last month) first non-LCG2 site: Univ. Wisconsin (joined last month)

12. 26-May-2005R. Mankel: Status of ZEUS12 Grid: ZEUS & Other Experiments In January, ZEUS production amounted to 16% of total CPU power in all UK grid sites In January, ZEUS production amounted to 16% of total CPU power in all UK grid sites running at very low priority (“opportunistic mode”) running at very low priority (“opportunistic mode”) LHCB ZEUS ATLAS

13. 26-May-2005R. Mankel: Status of ZEUS13 Physics Highlights Many essential results still coming from HERA-I data Many essential results still coming from HERA-I data 8 papers published since last PRC 8 papers published since last PRC HERA-II data are under analysis HERA-II data are under analysis still less statistics than HERA-I, but increasing still less statistics than HERA-I, but increasing also first results from fresh e – data also first results from fresh e – data

14. 26-May-2005R. Mankel: Status of ZEUS14 First Impact of New e  p Data: D* About equal sample sizes of e + and e  data in HERA-II About equal sample sizes of e + and e  data in HERA-II Already 2x as much integrated e  p luminosity compared to HERA-I Already 2x as much integrated e  p luminosity compared to HERA-I  Time to revisit an old puzzle… D *+  D 0  +  (K   + )  + e+pe+p e-pe-p 40 pb -1 33 pb -1 m(D 0  + )  m(D 0 )

15. 26-May-2005R. Mankel: Status of ZEUS15 D* in New Data (cont’d) There is no obvious mechanism that should lead to different D* cross sections for e  p and e  p scattering There is no obvious mechanism that should lead to different D* cross sections for e  p and e  p scattering Still, an indication of such an asymmetry was seen in the HERA-I data Still, an indication of such an asymmetry was seen in the HERA-I data r(e  p)/ r(e  p)=1.67  0.21 (Q 2 >40 GeV 2 ) r(e  p)/ r(e  p)=1.67  0.21 (Q 2 >40 GeV 2 ) statistical fluctuation, or mysterious anomaly? statistical fluctuation, or mysterious anomaly? Charm production by boson- gluon fusion

16. 26-May-2005R. Mankel: Status of ZEUS16 D* in New Data (cont’d)  HERA-II data with increased e  p statistics do not show this anomaly any more

17. 26-May-2005R. Mankel: Status of ZEUS17 Total bb Cross Section Traditional analysis tags single B hadrons (e.g. with  ) example: p t rel study sensitive to fast B hadrons strong cuts into phase space to suppress background Tagging of both B’s makes use of the correlation allows low p t μ thresholds is sensitive to B hadrons that are practically at rest  measures total bb cross section double tag HERA-I Data

18. 26-May-2005R. Mankel: Status of ZEUS18 Di-Muons: Data vs MC  Good overall description with MC  bb contribution ~2000 events, purity ~43% Same-charge combinations used to normalize light-flavor background Same-charge combinations used to normalize light-flavor background non-isolated, E T >8 GeV

19. 26-May-2005R. Mankel: Status of ZEUS19 bb Cross Section from Di-Muon Events (cont’d) NLO QCD predictions: PHP: 5.8 nb NLO QCD predictions: PHP: 5.8 nb (FMNR,CTEQ5M) DIS: 1.0 nb (FMNR,CTEQ5M) DIS: 1.0 nb (HVQDIS,CTEQ5F4) (HVQDIS,CTEQ5F4)  6.8 nb  6.8 nb  NLO prediction lower than the data  applied first time at HERA +3.0–1.7 this analysis D*μ PHP D*μ DIS

20. 26-May-2005R. Mankel: Status of ZEUS20  s Determination From NLO QCD Fits Recently, parton distribution functions have been obtained by a rigorous fit to combined inclusive DIS & jet data Recently, parton distribution functions have been obtained by a rigorous fit to combined inclusive DIS & jet data uncertainty of the mid-to-high x gluon distribution in inclusive DIS is very effectively constrained by the jet cross sections uncertainty of the mid-to-high x gluon distribution in inclusive DIS is very effectively constrained by the jet cross sections  sufficient sensitivity to determine PDFs entirely in one experiment Gluon distribution: relative uncertainty in bins of Q 2 10

21. 26-May-2005R. Mankel: Status of ZEUS21  s Determination From NLO QCD Fits (cont’d) This method can also be used to determine  s (M Z ) as a free parameter in the fit This method can also be used to determine  s (M Z ) as a free parameter in the fit  s (M Z ) = 0.1183  0.0028 (exp.)  0.0008 (model)  0.0050 (th.)  in agreement with world average  s (M Z )=0.1182  0.0027  first precise determination of  s from HERA data alone world average (Bethke 2004):

22. 26-May-2005R. Mankel: Status of ZEUS22 Strong Coupling Constant Comprehensive average of  s (M Z ) measurements at HERA Comprehensive average of  s (M Z ) measurements at HERA conservative assumptions on correlations of theoretical uncertainties (higher order, PDFs, hadronisation) conservative assumptions on correlations of theoretical uncertainties (higher order, PDFs, hadronisation)   s (M Z )=0.1186  0.0011 (exp)  0.0050 (th) experimental uncertainty ~0.9%, theoretical ~4% experimental uncertainty ~0.9%, theoretical ~4%  Need for NNLO calculations C. Glasman, DIS2005

23. 26-May-2005R. Mankel: Status of ZEUS23 NC Cross Section at High x High-x region is hard to measure High-x region is hard to measure for current jet at very low angle,  had is either badly resolved, or the jet is not detected at all for current jet at very low angle,  had is either badly resolved, or the jet is not detected at all  x range ends at 0.65  limits determination of PDF at large x

24. 26-May-2005R. Mankel: Status of ZEUS24 NC Cross Section at High x (cont’d) New approach beyond classical “double angle method”: New approach beyond classical “double angle method”: use jet finder & determine x from E jet and  jet use jet finder & determine x from E jet and  jet x  E jet  good resolution x  E jet  good resolution if no jet distinguishable, classify event into integrated bin (x max <x<1) if no jet distinguishable, classify event into integrated bin (x max <x<1) One jet Zero jet e+e+ e+e+

25. 26-May-2005R. Mankel: Status of ZEUS25 NC at High x: Data vs. Theory  Good agreement with PDFs  This method applied first time at HERA

26. 26-May-2005R. Mankel: Status of ZEUS26 Rapidity Gaps at High Q 2 Interest in diffraction at high Q 2 extends far beyond HERA Interest in diffraction at high Q 2 extends far beyond HERA clean final states at LHC, e.g. for Higgs? clean final states at LHC, e.g. for Higgs? Test factorization of diffractive component of proton Test factorization of diffractive component of proton At last PRC, first results for charged currents were shown At last PRC, first results for charged currents were shown statistics did not allow to measure Q 2 dependence statistics did not allow to measure Q 2 dependence Large rapidity gap  Look for rapidity gaps in neutral current events  Compare with charged current analysis

27. 26-May-2005R. Mankel: Status of ZEUS27 Rapidity Gaps in NC Events Forward Plug Calorimeter (FPC) Rapidity gap “Normal” DIS MC (Ariadne) clearly insufficient at low  max “Normal” DIS MC (Ariadne) clearly insufficient at low  max  Need Ariadne+RAPGAP (diffractive MC) to describe the data with FPC veto (at beam pipe) 5

28. 26-May-2005R. Mankel: Status of ZEUS28 Rapidity Gaps in NC: Q 2 Dependence  Sizable diffractive contribution to NC cross section drops with rising Q 2 still 2% at Q 2 =1500 GeV 2  NC and CC compatible For comparison: Low-Q 2 Data High -Q 2 NC x P <0.05

29. 26-May-2005R. Mankel: Status of ZEUS29 Exclusive Electroproduction of Vector Mesons (new:  ) Very clean final state, large kinematical range Very clean final state, large kinematical range At HERA, observe transition from soft to hard regime At HERA, observe transition from soft to hard regime Present set of measurements: ,  (new), J/  Present set of measurements: ,  (new), J/  Differential cross sections show high sensitivity to the gluon density functions Differential cross sections show high sensitivity to the gluon density functions  challenge to understand diffractive scattering quantitatively

30. 26-May-2005R. Mankel: Status of ZEUS30  Electroproduction: Signature scattered electron K+K–K+K– Reconstructed electron + 2 charged tracks Reconstructed electron + 2 charged tracks Otherwise detector completely empty Otherwise detector completely empty Scattered proton escapes near beam line Scattered proton escapes near beam line 3642  signal events 3642  signal events

31. 26-May-2005R. Mankel: Status of ZEUS31 VM Electroproduction: W Dependence  Highly sensitive not only to different models, but also to different gluon densities within the same model J/ 

32. 26-May-2005R. Mankel: Status of ZEUS32  Electroproduction: Q 2 Dependence Clean separation of  L and  T components challenges models Clean separation of  L and  T components challenges models good qualitative description, in particular  T good qualitative description, in particular  T better overall agreement with FS04 model better overall agreement with FS04 model  Excellent sector for further optimizations of pQCD calculations

33. 26-May-2005R. Mankel: Status of ZEUS33 Summary Encouraging data rates from HERA-II Encouraging data rates from HERA-II Detector & data chain in good shape Detector & data chain in good shape MC mass production on computing grid MC mass production on computing grid Wealth of new physics results Wealth of new physics results  Looking forward to a fruitful data-taking period with a huge data sample & post- upgrade detector and polarization and polarization

34. 26-May-2005R. Mankel: Status of ZEUS34 The End

35. 26-May-2005R. Mankel: Status of ZEUS35 Backup Slides

36. 26-May-2005R. Mankel: Status of ZEUS36 More Pieces to Pentaquark Puzzle  (1520) : both in forward & backward hemisphere  + : only in forward hemisphere signal mainly from forward pseudo rapidity region  + signal mainly from forward pseudo rapidity region unlike regular baryons unlike regular baryons  (1520) and  c predominantly at medium Q 2 similar to  c no sign of decuplet partners seen in  –  – and  –  + (  NA49)

37. 26-May-2005R. Mankel: Status of ZEUS37 Di-Muon Mass Spectra (Data vs MC) low mass high mass same B (charm cascade) + J/  different B’s (signal!) + cc + light flavor BG mainly light flavor BG different B’s (charm cascade + BB mixing) + light flavor BG  Good description with MC  bb contribution ~2000 events

38. 26-May-2005R. Mankel: Status of ZEUS38 bb Cross Section: a Di-Muon Event

39. 26-May-2005R. Mankel: Status of ZEUS39 bb from Di-Muons: Normalization of BG-MC cc: normalize to D*mu analysis cc: normalize to D*mu analysis Bethe-Heitler, elastic charmonium: normalize to data under isolation cut Bethe-Heitler, elastic charmonium: normalize to data under isolation cut Light flavor: use like sign spectrum (minus bb MC) Light flavor: use like sign spectrum (minus bb MC)

40. 26-May-2005R. Mankel: Status of ZEUS40 NC Cross Section at High x (cont’d) Considerable extension of kinematical region towards high x, in particular for moderate Q 2 (zero jet case) Considerable extension of kinematical region towards high x, in particular for moderate Q 2 (zero jet case) Improved x resolution (one jet case) Improved x resolution (one jet case) Only 99-00 e + data used so far (65 pb -1 ) Only 99-00 e + data used so far (65 pb -1 )

41. 26-May-2005R. Mankel: Status of ZEUS41  Electroproduction: W Spectrum  ~W   ~W  Test scaling of  with (Q 2 +M V 2 ) Test scaling of  with (Q 2 +M V 2 )  J/  is always hard   hardness increases with Q 2   shows intermediate behavior

42. 26-May-2005R. Mankel: Status of ZEUS42 J/  Electroproduction Theory vs Exp shown by T. Teubner at DIS2005