1. B. List, ETH Zürich Page 1 Report from H1: PRC Open Session, 30.10.2002 H1: Status and Prospects Benno List Institute for Particle Physics, ETH Zürich + New Physics Results + Operation: Progress and Problems + Status of Upgrade Projects + Plans

2. B. List, ETH Zürich Page 2 Report from H1: PRC Open Session, 30.10.2002 Physics Results for the Summer Successful conference season: Amsterdam: + 46 contributed papers + 9 Talks New Preliminary Results: + High Q 2 NC/CC data from full HERA-I dataset, with QCD fits + F 2 D at low Q 2 + Diffractive dijet photoproduction + Forward jet production + Prompt photon production + W production with hadronic decays + Search for doubly charged Higgs

3. B. List, ETH Zürich Page 3 Report from H1: PRC Open Session, 30.10.2002 Final High-Q 2 Cross Sections + Full HERA-I data set has been analyzed + Q 2 = 100 - 30000 GeV 2, X=0.0013 - 0.65 + Cross section shows nicely the unification of electromagnetic and weak interactions.

4. B. List, ETH Zürich Page 4 Report from H1: PRC Open Session, 30.10.2002 Parton Distribution Fits Fit what is experimentally accessible: U=u+c D=d+s F 2 ~ (U+U) + (D+D) xF 3 ~2(U-U) +(D-D)  + ~ U+(1-y) 2 D  - ~ U+(1-y) 2 D 9 4 9 1 CC BCDMS p and d large x data important H1-only fit in remarkable agreement

5. B. List, ETH Zürich Page 5 Report from H1: PRC Open Session, 30.10.2002 Diffractive Dijets: DIS vs.  p + H1 diffractive parton densities predict dijet rate + At Tevatron: suppression by factor ~10: Gap destruction by spectator interactions + In photoproduction at H1: Expect behaviour similar to hadron- hadron scattering, but: Far less gap destruction! Factor 10

6. B. List, ETH Zürich Page 6 Report from H1: PRC Open Session, 30.10.2002 Prompt Photons in Photoproduction  Photon radiation off quarks in  p interactions: Nice QCD test  Challenge: Separate  s from  0 s! + Leading order MC (Pythia, not shown) is low, NLO fits.  Hint of discrepancy with NLO from ZEUS data at low  is not confirmed.

7. B. List, ETH Zürich Page 7 Report from H1: PRC Open Session, 30.10.2002 Doubly Charged Higgs? + H ++ : Possible explanation for anomaly in di- and trilepton analyses + Dedicated analysis: Events observed in H1 are not compatible with H ++ production (only 1 event survives) + First search for single production of doubly charged Higgs bosons, triggered new analyses of LEP2 data The 6 events from the di- and trilepton analysis. Only one event survives the H++ analysis cuts.

8. B. List, ETH Zürich Page 8 Report from H1: PRC Open Session, 30.10.2002 A Taste of Luminosity Width 7.9MeV K S Peak 0 SpaCal kinematic peak Before......and after Calibration High-Q 2 event selection: E-pz peak, data vs. MC L int =0.68pb -1 Analysis in OO framework

9. B. List, ETH Zürich Page 9 Report from H1: PRC Open Session, 30.10.2002 Background Situation ep collider: ''worst of both worlds'' (read: ''most challenging''): + Beampipe heating by synchrotron radiation from positrons => Bad vacuum + High pp cross section (40mbarn) => high p induced background Design currents for HERA-II are not substantially higher than at HERA-I, detector limits are the same, nevertheless: Background does currently not allow data taking at design beam currents due to excessive chamber currents and radiation dose for silicon detectors.

10. B. List, ETH Zürich Page 10 Report from H1: PRC Open Session, 30.10.2002 Current Limit in CJC (Drift Chamber) Target: I e =55mA, I p =135mA I e I p = 7425mA 2 => We need a huge improvement over current situation. N.B.: Similar limits from radiation dose for silicon. Drift chamber operation limits currents to I e I p < 1000mA 2 Drift chamber current versus positron (proton) beam current Operation limit (ageing of chamber) Dynamic vacuum increase due to positrons Proton induced background

11. B. List, ETH Zürich Page 11 Report from H1: PRC Open Session, 30.10.2002 Proton Induced Background Beam proton scatter off residual gas nuclei. Particles hit H1 directly or after secondary scattering. Vertex distribution of random triggered events in a proton-only run Secondary scattering off C5B C5A C5B Beam Proton Primary interaction with gas nucleus Secondary Particle

12. B. List, ETH Zürich Page 12 Report from H1: PRC Open Session, 30.10.2002 Proton Induced Background, cont'd MC studies show: The collimators are not the problem. What has changed compared to 2000? Pressure? Gas composition? + Indications for presence of medium-heavy nuclei (C, O) in addition to H (CH 4 ?) + Source of vacuum problem unclear. Must be identified before shutdown.

13. B. List, ETH Zürich Page 13 Report from H1: PRC Open Session, 30.10.2002 Status of Upgrade Projects Forward Tracker FTD Forward Silicon Tracker FST Central Inner Propchamber CIP Fast Track Trigger FTT Very Forward Proton Spectrometer VFPS 200m in the tunnel

14. B. List, ETH Zürich Page 14 Report from H1: PRC Open Session, 30.10.2002 Forward Silicon Tracker FST + All sensors operational + Very good Signal/Noise = 32 + Simulation&Reconstruction work + Alignment in Progress Resolution: 12  m S/N=32 FST Event with 7 fitted tracks

15. B. List, ETH Zürich Page 15 Report from H1: PRC Open Session, 30.10.2002 Forward Tracker A high-Q2 event with reconstructed tracks in the upgraded forward tracker + 5 new chambers installed additional to 9 existing ones => increased redundancy + About 85% of channels are operational + Hit efficiency ~98%

16. B. List, ETH Zürich Page 16 Report from H1: PRC Open Session, 30.10.2002 Central Inner Propchamber CIP 5 Layer proportional chamber Allows to reconstruct z position of vertex for triggering purposes + Broken readout chips and cooling problem: only 2-3 layers out of 5 available => Insufficient for trigger => Needs repair in shutdown + Everything else works! Reconstructed vs. expected hit position of cosmics tracks through CIP show expected z resolution.

17. B. List, ETH Zürich Page 17 Report from H1: PRC Open Session, 30.10.2002 Fast Track Trigger FTT Status: + All hardware has been delivered and tested O.K. + Programming of chips 80% completed + Commissioning hardware, debugging firmware + FTT expected to be fully operational next summer First analog hits seen Hardware existing The FTT uses 12 drift chamber layers for a fast track fit with good momentum resolution

18. B. List, ETH Zürich Page 18 Report from H1: PRC Open Session, 30.10.2002 Very Forward Proton Spectrometer VFPS Measures diffractively scattered protons: E' p ~920GeV, p t <0.7GeV Located 200m away from IP in region with sc proton magnets + Cold bypass for helium in production, detectors are being tested with cosmics + Ready for installation in coming shutdown Design of the bypass at 200m Construction of the bypass Roman Pot detectors

19. B. List, ETH Zürich Page 19 Report from H1: PRC Open Session, 30.10.2002 Physics before the Shutdown F 2 c: Can be measured with FST and forward tracker Projection with 10pb -1 shows potential for interesting measurement MC study showing the possible statistical accuracy of an F 2 c measurement with 10pb -1 using the new H1 forward detectors

20. B. List, ETH Zürich Page 20 Report from H1: PRC Open Session, 30.10.2002 Physics plans, cont'd Polarized e+p scattering: A central HERA-II task!  =  0 (1+P/2) The chiral structure of the standard model has never been tested in ep scattering.

21. B. List, ETH Zürich Page 21 Report from H1: PRC Open Session, 30.10.2002 Requests for Running + Understanding background has priority + Currents: I e I p ~ 1000 mA 2 + Integrated Luminosity of 10pb -1 + Polarization We look forward to continued cooperation with the machine group and the other HERA experiments and anticipate a rapid solution to our background problems.

22. B. List, ETH Zürich Page 22 Report from H1: PRC Open Session, 30.10.2002 Conclusions + Backgrounds are the dominant problem + Understanding of backgrounds has much improved: We need a better vacuum + H1 is ready to take and analyze data + Shutdown of 17 weeks needed to reach optimal H1 performance + 1fb -1 is still the goal for HERA-II

23. B. List, ETH Zürich Page 23 Report from H1: PRC Open Session, 30.10.2002 Radiation Monitor + Limit: 50 kHz + Limits e+ current to 25mA + Independent system, results in similar constraints as from chamber currents

24. B. List, ETH Zürich Page 24 Report from H1: PRC Open Session, 30.10.2002 New Geometry in Simulation Thinner C5B: 20  5mm Lead Shielding New C6 Collimator Supermassive C5B

25. B. List, ETH Zürich Page 25 Report from H1: PRC Open Session, 30.10.2002 Synchrotron Radiation After magnet alignment in interaction region: + Impact on experiment as high as expected + Important, but not dominant contribution to chamber currents + Can be reduced by factor 1.8 by coating absorber at 10.8m Hit timing in central drift chamber (positron only run) Particle events (>10 hits): in time Synrad events (<5 hits): delayed arrival of reflected rays T=0

26. B. List, ETH Zürich Page 26 Report from H1: PRC Open Session, 30.10.2002 Electron-Gas Scattering Positron-Gas: Particles => „high“ multiplicity events SynRad: Few (<5-20) hits per event Determine ratio of chamber currents from positron-gas and synchrotron radiation Extrapolation: ratio ~1:1 for design current Ie=55mA, but will improve with better vacuum Monte Carlo simulations planned. Ratio of chamber current from electron-gas and synchrotron ration, as function of positron beam current

27. B. List, ETH Zürich Page 27 Report from H1: PRC Open Session, 30.10.2002 Background summary + Synchrotron radiation + Understood, not larger than expected (big achievement by HERA!), not the dominant problem for H1 + Reduction possible by factor 1.8 possible, will increase budget for proton background + Positron-gas scattering + Deserves more study, but not dominant at H1 + Proton induced background + By far dominant contribution to chamber currents + Mechanism well understood, good Monte Carlo models available + Open question: Vacuum. What has changed: pressure, composition? Why? What are the remedies?

28. B. List, ETH Zürich Page 28 Report from H1: PRC Open Session, 30.10.2002 Synchrotron Radiation Beampipe H1 C5A, C5B

29. B. List, ETH Zürich Page 29 Report from H1: PRC Open Session, 30.10.2002 Jet Trigger + Project suffered from leave of important persons + Now back on track + Motherboards currently being tested + „Bump finder cards“ in production + Completion Sep. '04

30. B. List, ETH Zürich Page 30 Report from H1: PRC Open Session, 30.10.2002 Central Jet Chamber CJC CJC Calibration in r  has already now similar quality as for reprocessed HERA- I dataset Mass 493.6MeV Width 7.9MeV K S Peak 0

31. B. List, ETH Zürich Page 31 Report from H1: PRC Open Session, 30.10.2002 Object Oriented Data Analysis

32. B. List, ETH Zürich Page 32 Report from H1: PRC Open Session, 30.10.2002 Operation

33. B. List, ETH Zürich Page 33 Report from H1: PRC Open Session, 30.10.2002 Operation: Problems  Background limits currents to 20mA e +, 30mA p (design: 58  130), otherwise excessive currents in drift chamber and radiation monitor + Background Task Force: + Common TF of machine and experiments + Good working climate + Much improved understanding of causes and possible remedies obtained in last three months + Written reports delivered (H1: 75 pages)

34. B. List, ETH Zürich Page 34 Report from H1: PRC Open Session, 30.10.2002 Proton-Gas Background A Typical Event from C5B C5B

35. B. List, ETH Zürich Page 35 Report from H1: PRC Open Session, 30.10.2002 CIP, cont'd CIPix chips have problems: bond wires broken under globtop cover due to thermal stress + Only 2-3 out of 5 layers operational + Problem understood + New cards will be produced + Exchange necessary to reach required performance CIPix- Chips

36. B. List, ETH Zürich Page 36 Report from H1: PRC Open Session, 30.10.2002 Central Inner Propchamber CIP Chamber is operational: + Optical data transmission works + Trigger logic works

37. B. List, ETH Zürich Page 37 Report from H1: PRC Open Session, 30.10.2002 Doubly Charged Higgs? + H ++ : Possible explanation for anomaly in di- and trilepton analyses + Dedicated analysis: Events observed in H1 are not compatible with H ++ production + First search for single production of doubly charged Higgs bosons, triggered new analyses of LEP2 data

38. B. List, ETH Zürich Page 38 Report from H1: PRC Open Session, 30.10.2002 Fast Track Trigger FTT Trigger Level 3: ~ 100  s + Event reconstructiona and particle identification (via resonances) on processor farm Trigger Level 3: ~ 100  s + Event reconstructiona and particle identification (via resonances) on processor farm

39. B. List, ETH Zürich Page 39 Report from H1: PRC Open Session, 30.10.2002 Plans + Running before the Shutdown + Activities during the shutdown + Running after the shutdown

40. B. List, ETH Zürich Page 40 Report from H1: PRC Open Session, 30.10.2002 Fast Track Trigger, cont'd Status: + All hardware is working fine + Programming of chips 80% completed + Commissioning hardware, debugging firmware + FTT expected to be fully operational after shutdown First analog hits seen Hardware existing

41. B. List, ETH Zürich Page 41 Report from H1: PRC Open Session, 30.10.2002 Plans for Shutdown + Repair CIP: + Possible in beam position + Repair takes 3 weeks + Remove and reinstall: SpaCal, BPC, Silicon: 3+10 weeks + Close detector: 1 week + Install VFPS + All in all: 17 weeks View of the backward region of H1 during CIP repair SpaCal has been removed, GG magnet is raised CIP has been partially drawn out