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COMPASS muon programme

Comprehensive overview of key findings and future directions presented during COMPASS week in Prague. Includes reports on SPSC meetings, program objectives, and physics results from muon and hadron beam programs.

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COMPASS muon programme

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  1. COMPASS muon programme • Alain Magnon • DAPNIA/SPhN (CEA Saclay) • On behalf of the COMPASS Collaboration COMPASS week, PRAGUE August 1st-52005

  2. Highlights about results, upgrades, prospects, - SPSC Villars meeting 22-28 Sept 2004 - SPSC71 meeting 3 May 2005 (G. Mallot) - SPSC72 meeting 5 July 2005 - Talks by Paolo P., Sonia H. & Alex K. (section 4) Vadim A. (section 5) 2006 & beyond ? Content COMPASS week, PRAGUE August 1st-52005

  3. Villars 2004 Report on the SPSC Villars Meeting September 22-28 2004 John Dainton University of Liverpool, GB (on behalf of the SPSC) COMPASS week, PRAGUE August 1st-52005

  4. Villars 2004 • Framework • Machines and Beams • Heavy Ions • Neutrinos • Soft and Hard Protons • Antiproton Physics • Flavour Physics • Other Topics • Summary COMPASS Report on the SPSC Villars Meeting September 22-28 2004 John Dainton University of Liverpool, GB (on behalf of the SPSC) Report on the SPSC Villars meeting by John Dainton, University of Liverpool (CERN-SPSC-2005-010 SPSC-M-730 February 28th 2005, available on Web) COMPASS week, PRAGUE August 1st-52005

  5. Bielefeld, Bochum, Bonn (ISKP, PI), Burdwan and Calcutta, CERN, Dubna (LPP, LNP), Erlangen, Freiburg, Lisbon, Mainz, Moscow (INR, LPI, MSU), Munich-LMU, Munich-TU, Nagoya, Prague (CU, CUT, TUL), Protvino, Saclay, Tel Aviv, Torino (Univ., INFN), Trieste (Univ.,INFN), Warsaw (SINS), Warsaw (TU) More than 220 physicists from 28 Institutes COMPASS Collaboration COMPASS week, PRAGUE August 1st-52005

  6. Muon beam programme Quarks and gluon polarisation in polarised (longitudinal) nucleons Transverse spin distribution Lambda polarisation Diffractive vector-meson production Physics programme Stephan Paul talk Hadron structure and spectroscopy • Hadron beam programme • Polarisibility of pions and kaons • (Primakoff reaction) • Exotics q-states, glue balls • Semi-leptonic decays of charmed baryons • Double charmed hadrons • GPDs (DVCS, HEMP) • - under consideration - Nicole d’Hose talk COMPASS week, PRAGUE August 1st-52005

  7. Spectrometer 2002 -> 2004 trigger-hodoscopes DW45 straws SM2 dipole Muon-filter2,MW2 HCAL1 RICH_1 Gem_11 ECAL2,HCAL2 SM1 dipole MWPC Gems Scifi Polarised Target SPS 160 GeV 2.108m/spill Muon-filter1,MW1 Veto straws,MWPC,Gems,SciFi Gems,SciFi,DCs,straws Silicon SciFi Micromegas,DC,SciFi COMPASS week, PRAGUE August 1st-52005

  8. COMPASS objectives Original programme set for about 5 years (1) of running at 150 days/year with 14.4s supercyle and eSPS = 80%. i.e. 7.2 105spills/year i.e. 1019 PoT/year (2 108m/spill) (1) HMC (4 years) - CHEOPS (2 years) COMPASS week, PRAGUE August 1st-52005

  9. Data taking 2002 – 2004 2002 2003 2004 Beam (1) 106days 90d 110d єSPS+BL(2).89 .63 .67 Preparation~30d 7d 3d єSpectro(3).77 .83 .87 Data taking (4) 44d 39d 61d muon (L/T) 33d/11d 30d/9d 47d/14d 2004 19d 4d 15d hadron (1) Scheduled beam excluding MDs (4) L/T Longitudinal/Transverse sharing ~ 80/20 (2) Inefficiency from SPS, beam line, etc (3) ~ 0.90 additional due to time needed to rotate spin and calibrate spectrometer COMPASS week, PRAGUE August 1st-52005

  10. Data taking 2002 - 2004 muon: 2002 + 2003 + 2004 -> 11.6 105 spills request: 7.2 105 spills/year  2.5 (proposal-year) We got ~ 1.6 (proposal-year) Pilot hadron run: 2004 -> ~ 0.7 105 spills COMPASS week, PRAGUE August 1st-52005

  11. Highlights (SPSC71 status report) : - g1 - transversity - L polarisation -DG/G from high pT hadron pairs -DG/G from open-charm - more … Physics results COMPASS week, PRAGUE August 1st-52005

  12. most precise measurement for 0.004 < x < 0.03 PLB 612 (2005) 154 new NLO QCD fit, precision of a0 improves factor 2(<Q2> = 4 GeV2) g1 of the deuteron 2002-2003 data COMPASS week, PRAGUE August 1st-52005

  13. single transverse-spin asymmetries (2002 data) - Collins: related to transverse quark distributions - Sivers : related to intrinsic kT Towards transversity h+ h- Collins PRL 94,202002 (2005) Sivers COMPASS week, PRAGUE August 1st-52005

  14. all asymmetries compatible with zero measure product of chiral-odd FF and transverse-PDF - is the analysing power of Collins FF small? or are the transverse parton distributions small? (proton-neutron cancellation in deuteron ?) try other polarimeters - interference FF of two hadrons - lambda polarisation Quark polarimeters COMPASS week, PRAGUE August 1st-52005

  15. Theoretical work on Sivers SSA • “Extracting the Sivers function from polarized SIDIS data and making predictions” • - Phenomelogical model whose parameters are constrained by HERMES proton measurements. • - COMPASS 2002 preliminary results for Sivers effect are in agreement with the model. • M. Anselmino et al. hep-ph/057181 • (including HERMES Prel. Results shown at DIS05) COMPASS week, PRAGUE August 1st-52005

  16. Theoretical work on Sivers SSA • “Predictions of Sivers • asymmetries on a proton • target” • M. Anselmino et al. hep-ph/057181 COMPASS week, PRAGUE August 1st-52005

  17. Expected accuracy for Collins asymmetries 2002 2002-4 2006 COMPASS week, PRAGUE August 1st-52005

  18. ΔG/G from Photon-Gluon Fusion • Strategies to suppress background: • 1) Open charm production: • q = c unique, no background • charm fragmentation, 1.2 D0 per event • D0 -> K-π+ (BR 4%), D*+(~20%) -> D0π+ • 2) High-pT hadron pair production:q=u,d,s background from • non PGF events & resolved g • pQCD scale set by: • 1) ŝ > 4mc2 or • 2) ŝ > (pt1+pt2)2 LOW STAT. HIGH STAT. Photon Gluon Fusion Needed since Q2 ~ 0 COMPASS week, PRAGUE August 1st-52005

  19. ΔG/G from high-pT hadron pair e, m h1 h2 N Photon Gluon Fusion Leading order Process QCD-Compton measured aLL: calculable partonic asymmetries R : Monte-Carlo (Lepto/Phytia depending on Q2) COMPASS week, PRAGUE August 1st-52005

  20. Q2 < 1GeV2 250000 evts Q2 > 1GeV2 28000 evts 2002 and 2003 data - pT,1, pT,2 > 0.7 GeV, p2T,1 + p2T,2 > 2.5 GeV2, - for statistical reasons use A|| / D - D depolarisation factor, - exact formula used in analysis high-pT hadron pairs Q2<1GeV2 Q2>1GeV2 COMPASS week, PRAGUE August 1st-52005

  21. more difficult than large Q2 contributions from resolved photons - spin dependent structure of the photon perturbative part calculable non-perturbative part: - min/max VMD scenarios (Glück, Reya, Sieg) - tuning of intrinsic kT partons in the photon nucleon parameters - tuning of fragmentation functions - tuning of intrinsic kTin nucleon high-pT hadron pairs: Q2<1GeV2 COMPASS week, PRAGUE August 1st-52005

  22. Gluon polarisation, high pT pairs Q2>1GeV2 : 2002-2003 data Q2<1GeV2: COMPASS week, PRAGUE August 1st-52005

  23. Gluon polarisation G = 2.48 G = 0.62 G = 0.16 GRSV2000 NLO fits to g1 m2 = 3 Gev2 ΔG/G (xg≈ 0.1) is small DG>1 disfavoured COMPASS week, PRAGUE August 1st-52005

  24. Open charm: D’s from D*’s • requiring the slow pion in D* → D πs→ K ππs D0 → K ππ0 COMPASS week, PRAGUE August 1st-52005

  25. Gluon polarisation, D0 & D* events 2002-2003 data DG/G = -1.08 +/- 0.73 <xg> = 0.15 +/- 0.08 COMPASS week, PRAGUE August 1st-52005

  26. Gluon polarisation G = 2.48 G = 0.62 G = 0.16 GRSV2000 NLO fits to g1 COMPASS week, PRAGUE August 1st-52005

  27. Figure of Merit for open charm • 2002 – 2004 -> 2006 • FoM(DG/G) • s(DG/G)=1/FoM1/2 • We work very hard to increase FoM FoM COMPASS week, PRAGUE August 1st-52005

  28. FoM increase in 2006 (with upgrades): New COMPASS magnet: 1.3 Rich upgrade: 1.5 Ecal: 1.2 K below threshold: 1.1 100 days of beam: 1.3 -> (~ .9) total: 3.4 -> (~2.4) Figure of Merit for open charm COMPASS week, PRAGUE August 1st-52005

  29. Large Angle Spectrometer 2002-3-4-6 DC1 DC2DC4Straws Initial lay-out end 2002 downstream of SM2 ~ 200 mrd COMPASS PT solenoid Modified ..... ~ 70 mrd SMC solenoid Straws: 1 1/2 21/2 DCs: 3 COMPASS week, PRAGUE August 1st-52005

  30. COMPASS Oxford Danfysik magnet • OD magnet presently tested and • instrumented in Saclay • Some delays ... • Magnet will be delivered to CERN • in November COMPASS week, PRAGUE August 1st-52005

  31. COMPASS OD magnet 1st attempt to get uniform field (24.06): encouraging 100 ppm Request is ≤ 100 ppm COMPASS week, PRAGUE August 1st-52005

  32. 3 m 6 m vessel mirror wall Photon Detectors: CsI MWPC 5 m radiator: C4F10 RICH (PDs) upgrade in 2006 COMPASS week, PRAGUE August 1st-52005

  33. central region ‘maPMT’: multi-anode PMTs lens system MAD4 preamp F1 TDCs, excellent time resolution outer region ‘APV’: keep CsI photodetector new readout based on APV chips good timing resolution ‘no’ DAQ dead time RICH upgrade in 2006 beam COMPASS week, PRAGUE August 1st-52005

  34. elements tested in T11 beam approved by INFN in April, design of optics finished, PMs ordered (600) delivery schedule Q3 2005 till Jan 2006 ready spring 2006 RICH maPMT Trieste, Turin + Bonn, Erlangen, Freiburg, Lisbon, Mainz, Prague (2) COMPASS week, PRAGUE August 1st-52005

  35. R/O successfully tested during 2004 on the Rich installation and test Q1 /06 BORA CONNECTOR +3.7V, -3.7V, GND 10 PIN HE10CONNECTOR +5V, -5V, GND 10 PIN HE14CONNECTOR 4 Differential ADC Outputs RJ45 CONNECTOR CLK, TRIGGER, I2C POWER_MUX ( STRAPS ) & +/- 3.3V Regulators x 4 Fanout +/- 3.3 or 3.7 V 4 differential amplifiers +/- 5V or +/-3.7V + & - 1.25V Regulator + & - 1.25V Regulator + & - 1.25V Regulator + & - 1.25V Regulator APV3 APV2 APV1 APV0 48 48 12 36 48 24 24 48 36 12 48 48 J8 J7 J6 J5 J4 J3 J2 J1 J0 Figure 1 : Block-diagram of the new board APV RICH project dR, cm Trigger time x25ns • Design based on GEM & Si FEE • Provides signal timing • accuracy <200ns TU-Munich, Saclay COMPASS week, PRAGUE August 1st-52005

  36. Chamber under construction by Saclay frames delivered assembly and test Q4/05-Q1/06 operational April 2006 Large drift chamber DC4 COMPASS week, PRAGUE August 1st-52005

  37. Plan to equip entire ECAL1 for 2006 (Protvino) Also beneficial for open- charm D0 → K ππ0 D*0 → D0π0s ECAL1 COMPASS week, PRAGUE August 1st-52005

  38. SPS in 2006 Schedule prepared by SPS Coordinator & proposed by SPSC COMPASS - 2006 = 3440 h–> 142 days COMPASS – (2004)= 3120 h–> 130 days 110(m) 20(h) COMPASS week, PRAGUE August 1st-52005

  39. SPS in 2006 Schedule was not accepted by CERN RB New (draft) schedule: • COMPASS – 2006’ • 2728 h–> 113 days (not 142 d) • restart of SPS etc … • єSPS+BL ~ 0.7 or lower • ~ 0.5 proposal year COMPASS week, PRAGUE August 1st-52005

  40. Conclusion • muon programme was for ~2.5 years (SPS proposal-years) • with 1.6 year of running, important physics results were • obtained, also : • - 3 physics papers (g1d, Collins/Sivers asym., penta-q search) • - DG/G with remarkable precision from high pT low Q2 • - s(DG/G) from D0 (0.73 -> 0.43 with 2004) COMPASS week, PRAGUE August 1st-52005

  41. Conclusion • Ambitious objective for 2006 • Complete proposed muon programme • - get error on DG/G from charm close to error of proposal, • - run both with deuteron & proton target • 1/ successful equipment upgrades • 2/ sufficient beam allocation from SPS (?) COMPASS week, PRAGUE August 1st-52005

  42. Additional slides COMPASS week, PRAGUE August 1st-52005

  43. s(h1d,h1p) vs acceptance COMPASS magnet SMC magnet COMPASS week, PRAGUE August 1st-52005

  44. Resolved photon contributions PYTHIA e.g.: qq’→ qq’ COMPASS week, PRAGUE August 1st-52005

  45. systematic error - determined using 15 independent MC simulations - exploring the parameter space in kT of nucleon and photon fragmentation functions parton shower on/off, renormalisation scale Example: kT tuning nucleon photon COMPASS week, PRAGUE August 1st-52005

  46. excellent to good agreement for all kinematics variables let’s get Data versus MC COMPASS week, PRAGUE August 1st-52005

  47. excellent to good agreement for all kinematics variables let’s get Data versus MC COMPASS week, PRAGUE August 1st-52005

  48. xBj < 0.05, can neglect QCD Compton and LO LEPTO tuning à la SMC high-pT high-pT hadron pairs: Q2>1GeV2 pT x p COMPASS week, PRAGUE August 1st-52005

  49. Open charm: MC studies pT z y • AROMA Monte Carlo, PGF only • background subtracted 2003 data (side bands) • D’s indeed from PGF ? Data understood? • good agreement data / MC • hard z-distribution COMPASS week, PRAGUE August 1st-52005

  50. aLLfrom one hadron from PGF reconstructed Correlation of generated and reconstructed aLL Analysis uses event weighting with aLLdeduced from hadron kinematic variables Open charm: MC studies COMPASS week, PRAGUE August 1st-52005

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