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experiment NA58

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experiment NA58

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  1. experiment NA58 The COMPASS experimentat CERN Oleg KouznetsovJINR, Dubna On behalf of the COMPASS Collaboration QUARKS2014, Suzdal 2-8 June

  2. Lake LEMAN LHC COMPASS CNGS GranSasso 732 km CERN (France) N SPS CERN (Suisse) QUARKS2014, Suzdal 2-8 June

  3. COmmonMuon and Proton Apparatus for Structure and Spectroscopy ~220 physicists 13 countries 23 Institutes COMPASS I 2002-2011 Muon beam Hadron beam QUARKS2014, Suzdal 2-8 June

  4. COmmonMuon and Proton Apparatus for Structure and Spectroscopy ~220 physicists 13 countries 23 Institutes COMPASS I 2002-2011 Muon beam Hadron beam Unpolarised physics Polarised physics QUARKS2014, Suzdal 2-8 June

  5. COmmonMuon and Proton Apparatus for Structure and Spectroscopy ~220 physicists 13 countries 23 Institutes COMPASS I 2002-2011 Muon beam Hadron beam Unpolarised physics Polarised physics Trans • polar. . Long. polar. Exc. V meson production  hyperonpolarization • Quark den- sitiesq Quark den- sitiesTq Gluon den- sitiesg Heavy hyperons QUARKS2014, Suzdal 2-8 June

  6. COmmonMuon and Proton Apparatus for Structure and Spectroscopy ~220 physicists 13 countries 23 Institutes COMPASS I 2002-2011 Muon beam Hadron beam Unpolarised physics Polarised physics Coulomb production Central production Diffractive scattering Trans • polar. . Long. polar. Exc. V meson production  hyperonpolarization • Quark den- sitiesq Quark den- sitiesTq Gluon den- sitiesg Heavy hyperons QUARKS2014, Suzdal 2-8 June

  7. COmmonMuon and Proton Apparatus for Structure and Spectroscopy ~220 physicists 13 countries 23 Institutes COMPASS I 2002-2011 Muon beam Hadron beam Unpolarised physics Polarised physics Coulomb production Central production Diffractive scattering Trans • polar. . Long. polar. Polarizabilities Exc. V meson production Glueballs Spectroscopy  hyperonpolarization • Quark den- sitiesq Hybrids Quark den- sitiesTq Multiquarks Gluon den- sitiesg Heavy hyperons QUARKS2014, Suzdal 2-8 June

  8. COMPASS in  runNIM A 577(2007) 455 Trigger Hodoscopes ECALs & HCALs MWPCs 50 m SM2 RICH mFilters/Walls SM1 Drift Chambers Straws GEMs Si Micromegas 160 GeV 190 GeV SciFi veto QUARKS2014, Suzdal 2-8 June

  9. COMPASS in  runNIM A 577(2007) 455 6LiD target  run Trigger Hodoscopes ECALs & HCALs MWPCs 50 m SM2 RICH mFilters/Walls SM1 Drift Chambers Straws GEMs Si Micromegas 160 GeV 190 GeV SciFi veto QUARKS2014, Suzdal 2-8 June

  10. COMPASS in  runNIM A 577(2007) 455 6LiD target  run Trigger Hodoscopes ECALs & HCALs MWPCs 50 m SM2 RICH mFilters/Walls SM1 LH2 target  run Drift Chambers Straws GEMs Si Micromegas 160 GeV 190 GeV SciFi veto QUARKS2014, Suzdal 2-8 June

  11. Outline Part I: nucleon spin structure Longitudinal spin structure Transverse spin and momentum structure of the nucleon By product result: heavy hyperon production rates in DIS QUARKS2014, Suzdal 2-8 June

  12. Outline Asymmetry measurement Part I: nucleon spin structure QUARKS2014, Suzdal 2-8 June

  13. Outline Data taken Part I: nucleon spin structure • 2002-2004 160 GeV m on 6LiD L,T • 2006 160 GeV m on 6LiD L • 2007 160 GeV m on NH3T • 2010 160 GeV m on NH3 T • 200 GeV m on NH3 L • 160 GeV on LH2 (GPD test) • Longitudinal spin structure • Transverse spin and momentum structure of the nucleon • By product result: heavy hyperon production rates in DIS QUARKS2014, Suzdal 2-8 June

  14. Outline Data taken Part I: nucleon spin structure • 2002-2004 160 GeV m on 6LiD L,T • 2006 160 GeV m on 6LiD L • 2007 160 GeV m on NH3T • 2010 160 GeV m on NH3 T • 200 GeV m on NH3 L • 160 GeV on LH2 (GPD test) • Longitudinal spin structure • Transverse spin and momentum structure of the nucleon • By product result: heavy hyperon production rates in DIS Part II: hadron reactions Hadron spectroscopy Tests of χPT QUARKS2014, Suzdal 2-8 June

  15. Outline Data taken Part I: nucleon spin structure • 2002-2004 160 GeV m on 6LiD L,T • 2006 160 GeV m on 6LiD L • 2007 160 GeV m on NH3T • 2010 160 GeV m on NH3 T • 200 GeV m on NH3 L • 160 GeV on LH2 (GPD test) • Longitudinal spin structure • Transverse spin and momentum structure of the nucleon • By product result: heavy hyperon production rates in DIS Part II: hadron reactions Before and After PWA This picture was taken from the talk of S.Paul who has been inspired by M.Pennington QUARKS2014, Suzdal 2-8 June

  16. Outline Data taken Part I: nucleon spin structure • 2002-2004 160 GeV m on 6LiD L,T • 2006 160 GeV m on 6LiD L • 2007 160 GeV m on NH3T • 2010 160 GeV m on NH3 T • 200 GeV m on NH3 L • 160 GeV on LH2 (GPD test) • Longitudinal spin structure • Transverse spin and momentum structure of the nucleon • By product result: heavy hyperon production rates in DIS • 190 GeV p-, m onPb(2 weeks) • 2008 190 GeV p-onLH2 • 190 GeV p,p+on LH2,Pb,Ni,W • 2012 190 GeVp-, m onNi (DY test) Part II: hadron reactions Hadron spectroscopy Tests of χPT QUARKS2014, Suzdal 2-8 June

  17. Outline Data taken Part I: nucleon spin structure • 2002-2004 160 GeV m on 6LiD L,T • 2006 160 GeV m on 6LiD L • 2007 160 GeV m on NH3T • 2010 160 GeV m on NH3 T • 200 GeV m on NH3 L • 2012 160 GeV on LH2 (GPD test) • Longitudinal spin structure • Transverse spin and momentum structure of the nucleon • By product result: heavy hyperon production rates in DIS • 190 GeV p-, m onPb(2 weeks) • 2008 190 GeV p-onLH2 • 190 GeV p,p+on LH2,Pb,Ni,W • 2012 190 GeVp-, m onNi (DY test) Part II: hadron reactions Hadron spectroscopy Tests of χPT • Part III: COMPASS-II or our future • SPS/LHC shutdown, 2015 (Polarized DY), 2016-2017 (GPD program) QUARKS2014, Suzdal 2-8 June

  18. Part I: nucleon spin structure 2010 E80 E130 E142/3 E154/5 EMC SMC COMPASS I HERMES CLAS/HALL-A Phenix/Star 1987 EMC Where does the proton really get its spin? Till now the “spin crisis” persists…………. QUARKS2014, Suzdal 2-8 June

  19. 1.Longitudinal spin structure QUARKS2014, Suzdal 2-8 June

  20. Nucleon spin puzzle since 1988 quarks gluons orb. mom. ½= ½ΔΣ + ΔG + <Lz> “past” “present” “future”experiments Measurement of ΔGis important for tworeasons: - as an element of nucleon spin puzzle - possible role of axial anomaly in thea0interpretation(a0≠ ΔΣ) a0(= ΔΣ) ismeasured to be ~0.30-0.35 instead of expected 0.6 a0 = QUARKS2014, Suzdal 2-8 June

  21. N Direct gluon polarization Δg/g from m N scattering COMPASS flagship measurement Photon Gluon Fusion (PGF) Open Charm → clean channel → but experimentally difficult  ≈ 100 nb… limited statistics High-pTHadron Pairs → easy to get a statistics → but physical background 2 cases Q2 <1 GeV2(90% stat) & Q2 > 1 GeV2 (10% stat) A||= RPGF<aLL> <g/g> + Abkg Spin asymmetry of cross sections for longitudinal polarizations of beam and target, parallel and antiparallel QUARKS2014, Suzdal 2-8 June

  22. Open charm (example) D0 → K π D* tag ND=8650 D0→ K π π0 only Also were used: D0 K D0 K0 (no 0rec) D0Ksub (no K ID) Total number: 86250 D0 mesons D0 → K π no D* tag ND=37750 QUARKS2014, Suzdal 2-8 June

  23. QCD- Compton LO DIS 10% of statistics high pT hadron pairs - considerably higher statistics … but physical background, resolved photons processes (last 4) are important only for low Q2  qg  gq qq gg   QUARKS2014, Suzdal 2-8 June

  24. 5 points from COMPASS World direct measurements on g/g in LO Phys. Lett. B 718 (2013) 922 Δg/g(x=0.09) = 0.125 ± 0.060 ± 0.063 All measurements compatible with 0 confirmed by polarised pp at RHIC Open charm NLO (first time) PRD 87 (2013) 052018 Δg/g(x=0.2) = -0.13 ± 0.15 ± 0.15 QUARKS2014, Suzdal 2-8 June

  25. A new LO extraction of gluon polarization from COMPASS DIS data The events in DIS region were re-analyzed and gluon polarization was extracted using the so called all-pT method. In this new method gluon polarization and leading process asymmetry are extracted simultaneously from the same data set using Neural Network approach. A reduction of both systematic and statistical uncertainties by more than 50% is achieved comparing to the published result PLB 718 (2013) 922. Δg/g(x=0.09) = 0.125 ± 0.060 ± 0.063 Presented at DIS2014 Warsaw, 28 April - 2 May 2014 Δg/g(x=0.1) = 0.113 ± 0.038 ± 0.035 QUARKS2014, Suzdal 2-8 June

  26. g1p world data • COMPASS 200 GeV • COMPASS 160 GeV • --- LSS QCD fit • Large set of data, extending to lower x and higher Q2region • Will beincluded in QCD global analyses

  27. 2.Transverse spin and momentum structure of the nucleon QUARKS2014, Suzdal 2-8 June

  28. Parton Distribution Functions three distribution functions are necessary to describe the spin structure of the nucleon at LO in the collinear case unpolarised PDF quark/gluon with momentumxPin a nucleon well known – unpolarized DIS q(x) f1q (x) helicity PDF quark/gluon with spin parallel to the nucleon spinin a longitudinally polarized nucleon known – polarized DIS Dq(x) g1q(x) transversity PDF quark with spin parallel to the nucleon spin in a transversely polarized nucleon DTq(x) h1q(x) poorly known – polarized SIDIS QUARKS2014, Suzdal 2-8 June

  29. Basic twist-2 PDFs of the nucleon • 8 intrinsic-transverse-momentum kTdependent PDFs at leading twist • Azimuthal asymmetries with different angular modulations in the hadron and spin azimuthal angles, Φh and Φs • Vanish upon integration over kT except f1 , g1 , and h1 Sivers Worm-gear-T g┴1T Boer– Mulders Transversity chiral -odd T -odd Pretzelosity QUARKS2014 Worm-gear-L h┴1L

  30. Twist-2 PDFs of nucleons f1 - density of partons in non-polarized nucleon, (x, Q2); g1-helicity , longitudinal polarization of quarks in longitudinally polarized nucleon; h1 -- transversity, transverse polarization of quarks in transversely polarized nucleon ; f┴1T- Sivers, correlation between the transverse polarization of nucleon (transverse spin) and the transverse momentum of non-polarized quarks; g┴1T- worm-gear-T, correlation between the transverse spin and the longitudinal quark polarization ; h┴ 1 - Boer-Mulders, distribution of the quark transverse momentum in the non-polarized nucleon ; h┴1L - worm-gear-L, correlation between the longitudinal polarization of the nucleon (longitudinal spin) and the transverse momentum of quarks ; h┴1T - pretzelosity, distribution of the transverse momentum of quarks in the transversely polarized nucleon QUARKS2014, Suzdal 2-8 June

  31. Transversity and Sivers azimuthal distribution of the inclusively produced hadrons correlationbetween the transverse polarisationof the nucleon and the transverse polarisation of the quark (non-zero because of Collins FF) transversity PDF Collins FF Sivers PDF correlation between the transverse spin of the nucleon and the transverse momentum of the quark (sensitive to orbital angular momentum) N.B. No data : Pretzelosity PDF h┴1T Worm-gear-L h┴1L Worm-gear-T g┴1T Boer-Mulders h┴ 1 QUARKS2014, Suzdal 2-8 June

  32. Collins asymmetry x > 0.032 region charged pions (and kaons), 2010 data COMPASS & HERMES results QUARKS2014, Suzdal 2-8 June

  33. ~12 ~ 4 Collins asymmetry same strength: a very important, not obvious result! QUARKS2014, Suzdal 2-8 June no strong Q2 dependence

  34. Collins asymmetry vs Global fit M. Anselmino et al., arXiv:1303.3822 (2013) fit to HERMES p, COMPASS p and d, Belle e+e- data QUARKS2014, Suzdal 2-8 June 2010 p data

  35. Siversasymmetry x > 0.032 region charged pions (and kaons), 2010 data COMPAS &HERMES results as for h+, smaller values measured by COMPASS; same indication for K+ QUARKS2014, Suzdal 2-8 June

  36. By product result: heavy hyperon production rates in DIS If you study  baryon it’s reasonable to have a look at hyperons also. QUARKS2014, Suzdal 2-8 June

  37. (1385) and (1321) hyperon and antihyperon production in DIS Decay channel (1385), (1321)   EPJC 73 (2013) 2581 Best hyperon statistics Example  (1321) signal 1147 ±49. 2320 ±68 QUARKS2014, Suzdal 2-8 June

  38. (1385) and (1321) hyperon and antihyperon production in DIS cont… First time the yields of antihyperons were measured in DIS Measured ratios Tuning of LEPTO/JETSET parameters related to the strange baryon productions was done fraction of indirectly produced (anti-) was found to be 37(32)% QUARKS2014, Suzdal 2-8 June

  39. Part II: Hadron reactions Gluon-richenvironment Rapidity gap Spin-exoticmesons Forwardkinematics Test of ChPT Radiative widths 2009 run 2008 run 2012 run QUARKS2014, Suzdal 2-8 June

  40. Mesons in the Constituent Quark Model Spin-parity rules for bound system Quark spins couple to total intrinsic spin S = 0 (singlet) or 1 (triplet) Relative orbital angular Momentum and total spin couple to meson spin Parity P = (_1)L+1 Charge conjugation C = (_1)L+S Forbidden JPC = 0-- , 0+-, 1-+, 2+-, 3-+, . . . QCD allows for states beyond the CQM Hybrids , glueballs , multi-quark states “Exotic” mesons have quantum numbers forbidden for Particularly interesting: JPC-exotic states QUARKS2014, Suzdal 2-8 June

  41. From old experiments: hybrids with JPC = 1−+ • Light meson sector exotics JPC=1-+: • p1(1400) • (E852, VES) • (Crystal Barrel) • (Crystal Barrel) • p1(1600) • (E852, VES) • (Crystal Barrel) • p1(2000) • (Crystal Barrel) The identification of exotics demands complete information on all neighbouring states and thus requires in particular: • Reconstruction of final states containing both neutral and charged particles • Observation of the same meson resonance in several different channels • Production of resonances in different reactions resonant nature controversial... QUARKS2014, Suzdal 2-8 June

  42. Diffractive pion dissociation  exotic 1(1600) state COMPASS, Phys. Rev. Lett. 104 (2010) 241803 2004 Data PWA analysis of 420000 events mom transfer 0.1 < t’< 1 (GeV/c)2 quasi-free nucleons in Pb a1(1260), a2(1320) and 2(1670) are clearly visible QUARKS2014, Suzdal 2-8 June

  43. -p +-- and 00- (2008/2009 data) -p  5-final state at low four-momentum transfer (2004 data) -p  and ’ (2008/2009 data) +- in central production pp  pfast+−pslow (2009 data) Spectroscopy using initial/final states with strangeness Beamintensity: 5·106 had/s Negative: 96% ,3.5% K Positive: 75% p, 25%  • A large amount of data were collected with hadron beam in 2008/2009 (10 – 100 times world statistics). Hadron reactions: processes & beam & statistics The hybrids, glueballs , multi-quark states are still “terra incognita” QUARKS2014, Suzdal 2-8 June

  44. Diffractive dissociation: 3p final states 420k events 96M events > 2.4M events • Target: 40 cm LH2 • Trigger: Recoil proton • RPD • Target: 3 mm Pb • Trigger: Multiplicity • No RPD • Cross-check: • tracking vs • ECAL Search for exotic JPC=1−+ in all 3 samples QUARKS2014, Suzdal 2-8 June

  45. Isobar Model and Analysis Partial Wave Analysis (PWA) in mass bins with up to 88 waves labelled JPC MIsobarL fit of spin-density matrix for major waves with Breit-Wigner as function of mass QUARKS2014, Suzdal 2-8 June

  46. a1(1420) QUARKS2014, Suzdal 2-8 June

  47. a1(1420) QUARKS2014, Suzdal 2-8 June

  48. a1(1420) QUARKS2014, Suzdal 2-8 June

  49. Results of Mass-Dependent Fit 1 new & 2 seen before states QUARKS2014, Suzdal 2-8 June

  50. Tests of χPT (Chiral Perturbation Theory) QUARKS2014, Suzdal 2-8 June