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HADRON SPECTROSCOPY AT COMPASS -- Exotic Hadrons at COMPASS --

HADRON SPECTROSCOPY AT COMPASS -- Exotic Hadrons at COMPASS --. Takahiro Iwata Yamagata University. on behalf of the COMPASS Collaboration. New Frontiers in QCD, February 5, 2010. OUTLINE. Introduction to COMPASS Physics in Hadron Spectroscopy

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HADRON SPECTROSCOPY AT COMPASS -- Exotic Hadrons at COMPASS --

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  1. HADRONSPECTROSCOPYAT COMPASS-- Exotic Hadrons at COMPASS -- Takahiro IwataYamagata University on behalf of the COMPASS Collaboration New Frontiers in QCD, February 5, 2010

  2. OUTLINE • Introduction to COMPASS • Physics in Hadron Spectroscopy • Diffractive dissociation to p-p-p+ • Diffractive dissociation to p-p0p0 • Central production of 4-charged-pions • p-h, p-hh channels • Kaonic final states: KKp, KK, Kp • Conclusion New Frontiers in QCD, February 5, 2010

  3. COMPASS NA58 experiment at CERNSPS COmmon Muon and Proton Apparatusfor Structureand Spectroscopy 20 Institutes/11 counties/~230 physicists Czech Republic, Finland, France, Germany, India, Israel, Italy, Japan, Poland, Portugal and Russia Bielefeld, Bochum, Bonn, Burdwan/Calcutta, CERN, Dubna, Erlangen, Freiburg, Lisbon, Mainz, Moscow, Munich, Prage, Protvino, Saclay, Tel Aviv, Torino, Trieste, Warsaw and Yamagata New Frontiers in QCD, February 5, 2010

  4. COMPASS at CERN Lake LEMAN COMPASS Airport LHC SPS CERN (France) N CERN (Suisse) 02/10/2014 BEACH08 26 june 2008 4 New Frontiers in QCD, February 5, 2010

  5. PHYSICS PROGRAMS OF COMPASS • Hadron program • hadorn-beams: • Runs : 2004, 08-09 • Hadron spectroscopy • Diffractive production • Search for new exotic states, glueballs or hybrids • Light meson spectroscopy Primakov scattering • Polarizabilities • （Doubly charmed baryons） • Muon program • pol-m beam: • Runs: 2002-04,06-07 • Nucleon Spin Structure • Gluon polarization DG/G • g1 spin structure function • Flavor decomposition of spin distributions • Transverse spin effects • Spin transfer in L-hyperon production • Vector meson production New Frontiers in QCD, February 5, 2010

  6. SETUP FOR MUON PROGRAM An experiment with pol. muon beam and pol. target at CERN • two stages spectrometer • Large Angle Spectrometer (SM1) • Small Angle Spectrometer (SM2) • tracking, calorimetry, PID(RICH/muon-filter) • High rate capability MuonWall SciFi Silicon Micromegas GEMs SM2 Straws SDC MWPC W45 E/HCAL 0.003 < x < 0.5 10-3 < Q2 < 10 GeV2 E/HCAL SM1 Polarized Target MuonWall RICH Pol. mbeam 160GeV/c Pol. 80% ｆrom SPS (CERN) • high energy beam • broad kinematical range • large angular acceptance NIM A 577(2007) 455 New Frontiers in QCD, February 5, 2010

  7. SETUP FOR HADRON PROGRAM Target: liquid H2, 40 cm long (Pb in 2004 pilot run) 2008-09 Beam: 190 GeV positive/negative hadrons Negative: 96% -, 3.5% K-, 0.5% p-bar Positive: 75% p, 25% +, 5% K+ Beam intensity: 2·107/s ( 108/spill, spill=4.8s, cycle=16.8s) P-id by beam Cherenkov Counter (CEDAR) New Frontiers in QCD, February 5, 2010

  8. TARGET PART IN HADRON PROGRAM RPD(Recoil Proton Detector) Installed in 2007 New Frontiers in QCD, February 5, 2010

  9. Physics in Hadron Spectroscopy New Frontiers in QCD, February 5, 2010

  10. PHYSICS GOALS • Objectives mainly in meson spectroscopy • QCD allows states which are forbidden in the quark Model • Exotic states • Glueballs: • Hybrids : • Tetraquarks : • Mixing with ordinary mesons with the same quantum numbers  complicated situation • Exotic JPC states : •  non-qq states : important to find them COMPASS contributes in the low mass region New Frontiers in QCD, February 5, 2010

  11. GLUEBALLS Quenched L-QCD prediction • Lightest glueballs: • scalar • tensor • Experimental candidate: • f0(1500) (Crystal Barrel, WA102) • JPC = 0++<< ordinary JPC •  mixing with ordinary mesons!  COMPASS [Y. Chen et al., Phys. Rev. D 73, 014516 (2006)] New Frontiers in QCD, February 5, 2010

  12. HYBRIDS Events / 0.04 GeV/c2 M(3p) (GeV/c2) • Light meson sector • hybrid candidate with exotics JPC=1-+: • p1(1400) (VES, E852, Crystal Barrel) • p1(1600) (E852, VES) • still controversial... 35 waves 20 waves [A.R. Dzierba et al., PRD 73, 072001 (2006)]  COMPASS [S.U. Chung et al., PRD 65, 072001 (2002)] New Frontiers in QCD, February 5, 2010

  13. PRODUCTION MECHANISMS Central production Diffractive dissociation • in forward direction • separate particles at • very small angles • Production of Isovectors • study hybrid states • Rapidity gap between pslow, hfast, X • Beam particle looses ~10% of its energy • Particles at large angles from X decays • Possible source of glueballs New Frontiers in QCD, February 5, 2010

  14. Diffractive Dissociation to p-p- p+ final State New Frontiers in QCD, February 5, 2010

  15. p -p -p +IN 2004 • Pilot run in 2004 ( 3 days ) • 190 GeV p- beam • 3mm thick Pb target • Diffractive dissociation from p- • Pomeron exchange • p- p- p+final state (4 M events) New Frontiers in QCD, February 5, 2010

  16. INVARIANT MASS OF 3p system 2004 COMPASS BNL E852 Pp=18 GeV/c 250 k events 0.08<t’<1.0 GeV2/c2 450 k events 0.1<t’<1.0 GeV2/c2 BNL E852 COMPASS Acceptance COMPASS acceptance is flat 50-60%, independent from the mass New Frontiers in QCD, February 5, 2010

  17. PARTIAL WAVE ANALYSIS Illinois/Protovino/Munich Program & BNL/Munich Program (independent cross-check) based on Isobar model Step 1. Mass-Independent PWA • 40 MeV/c2 mass bin • Gottfried-Jackson frame ( z//beam ) • 42 partial waves: JPCMe Y L • Y :isobars (pp)S, f0(980), r(770), f2(1270), r3(1690) • Background wave • fit in extended maximum likelihood Step 2. Mass-Dependent c2 fit • fit the results of step 1 • Parameterized by Breit-Wigner • 6 waves + coherent background M: absolute value of the spin projection to the z axis New Frontiers in QCD, February 5, 2010

  18. MAJOR WAVES New Frontiers in QCD, February 5, 2010

  19. JPC=1-+ EXOTIC WAVE 1-+ phase to 1++ p1(1600): 1-+ p1(1600): 1-+ a1(1260): 1++ phase motion 1-+ phase to 2-+ p2(1670): 2-+ p1(1600): 1-+ No phase motion Non-resonant B.G. due to Deck-effect Phys. Rev. Lett. 13, 169 (1964). Submitted to Phys.Rev. Lett.

  20. p -p - p +IN 2008 190 GeV/c negative hadron beam; P-id by beam line Cherenkov Counter  96% p-, 3.5% K-, 0.5% p-bar 40 cm liquid hydrogen target Spectrometer upgrade before 2008 run RPD, Silicon, Pixel GEM Exclusive measurements X10 BNL E852 statistics for full 2008 data Exclusivity cut [180-190 GeV] After all cuts New Frontiers in QCD, February 5, 2010

  21. PWA FOR 2008 p -p -p + PWA has been started Illinois/Protovino/Munich Program. Same wave set (42 waves) . No acceptance correction applied yet. 2++ total(e=+) Dominant waves 2-+ total(e=+) 1++ total(e=+) New Frontiers in QCD, February 5, 2010

  22. Diffractive Dissociation to p-p0 p0 final State New Frontiers in QCD, February 5, 2010

  23. p -p 0 p 0IN 2008 Isospin partner to p-p-p+ Consistency check Different isobars in decay chain New Frontiers in QCD, February 5, 2010

  24. 1ST ATTEMPT OF PWA FOR p - p 0 p 0 PWA : Illinois/Protovino/Munich Program Isobars: No acceptance correction applied yet. Relative intensities of charged and neutral modesare consistent with the isobar decays 2++rp a2(1280) Intensities normalized to a2 1++rp a1(1260) 2-+ f2p p2(1670) New Frontiers in QCD, February 5, 2010

  25. Central Production of 4-charged-pions (p– pp–fast p+ p- p+ p- p) New Frontiers in QCD, February 5, 2010

  26. + p- p+ p- IN CP p– pp–fast(p+ p- p+ p– ) pslow Study glueballs ( f0 and f2 families) Central Production( CP) p-fast p- p- p+ X p+ p- p pslow New Frontiers in QCD, February 5, 2010

  27. ENHANCEMENT OF CP Enhancing CP with Feynman X: COMPASS 0++rr ? WA102 f0(1450) f1(1285) f2(1900) f1 p+p-h p+p-p+p- (p0) h’  p+p-h p+p-p+p- (p0) PWA is prepared in COMPASS WA102(Phys.Lett.B413:217-224,1997) New Frontiers in QCD, February 5, 2010

  28. p–pp–hp, p–pp–hhp New Frontiers in QCD, February 5, 2010

  29. p - hCHANNEL p– p p– h p (2g) Constraint 1 h with confidence level > 10% h event selection • exotic Jpc=1-+ , p1(1400) ph? p-h p1(1400) ? • Amplitude analysis with 150k events in progress • Better statistics expected with calorimeter calibration(2008 data) • and LASER and LED monitor (2009 data) New Frontiers in QCD, February 5, 2010

  30. p - hh CHANNEL p– p p– h h p (4g) Fit on two h mass constraint: confidence level > 10% ( for each combination) hh event selection p0 background rejected Hybrid ? 3 combinations / event p-hh Projection New Frontiers in QCD, February 5, 2010

  31. p - h andhhIN p - hh CHANNEL p -h • exotic Jpc=1-+ , p1(1400) ph • glueball candidate f0(1500) hh • Structure at 1.5GeVinhh p1(1400); exotic Jpc state :glueball ? • Amplitude analysis with 5k events for ph and hh in progress • Better statistics expected with calorimeter calibration(2008 data) • and LASER and LED monitor (2009 data) hh hh New Frontiers in QCD, February 5, 2010

  32. Kaonic Final States: p– pK+K – p–p, p – pKs0Ks0p– p, …. New Frontiers in QCD, February 5, 2010

  33. KAONIC FINAL STATES • Glueball candidates decaying into KK • f0(1380),f0(1500): qq mixing with gg ? • Hybrid candidates decaying into KKp • p(1800): usual 31S0 or Hybrid? Accessible channels: p– pK+K – p– p,  This talk p – pKs0Ks0p– p,  This talk K – p K –p–p+ p, p – pKs0KL0p– p, …. same with positive charged beam New Frontiers in QCD, February 5, 2010

  34. KK SUBSYSTEM Allowed Jpc for different combinations of KK K+ K- identified by RICH: 10 GeV/c < PK < 30 GeV/c  Cut in acceptance  Neutral channels pick out the subsets RICH Event selection K+K – Ks0Ks0 range for kaon-id. • 3 charged (+--) tracks • One negative track identified as K- by RICH Two displaced vertexes for Ks New Frontiers in QCD, February 5, 2010

  35. KpINVARIANT MASS • Expected structures for • K*(892): 13S1 • K*(1410):23S1, • K0*(1430):13P0 , • K2*(1430): 11D2 K +p - • Acceptance in the low mass region is affected by RICH threshold. • p contamination in P-id • Almost background free • the structures are also visible. Ks0p - New Frontiers in QCD, February 5, 2010

  36. KK INVARIANT MASS K + K - • Known resonances visible in both mass spectra: • f0(1500): glueball candidate • f2‘(1520): 13P2 Ks0Ks0 New Frontiers in QCD, February 5, 2010

  37. KKpINVARIANT MASS K + K -p - • Structures around • 1.8 GeV and 2.2GeV Ks0Ks0 p - New Frontiers in QCD, February 5, 2010

  38. Kp v.s. KKpin K+K-p - X(2.2GeV)K *(890)+ K - / Kp(1400-1500) + K - X(1.8GeV)K *(890)+ K - New Frontiers in QCD, February 5, 2010

  39. Kpv.s. KKpin Ks Ks p - X(2.2GeV)K *(890)+ Ks/ Kp(1400-1500) + Ks X(1.7GeV)K *(890)+ Ks New Frontiers in QCD, February 5, 2010

  40. KKv.s. KKpin K+K-p - X(2.2GeV) (f /a0/f0) +p–  KK(1600 ) + p- X(1.8GeV)KK(1500 )+ p- New Frontiers in QCD, February 5, 2010

  41. KKv.s. KKp in Ks Ksp - a0(980)/f0(980) Quite different form K+K-p-due to allowed JPC=0++,2++,4++ for KsKs m(Ks0Ks0p-)/GeV f0(1500) f0(1380) m(Ks0Ks0)/GeV New Frontiers in QCD, February 5, 2010

  42. NEXT STEPS IN KKpCHANNELS • Mass-independent PWA to be performed • Enhancing central production for KK system FASTEST-p Selection Ks0Ks0 Ks0Ks0 New Frontiers in QCD, February 5, 2010

  43. CONCLUSION • COMPASS is a multi-purpose spectrometer • Muon program for nucleon spin structure • Hadron program mainly for hadron spectroscopy • COMPASS has started studies on spectroscopy • VERY high statistics ( partly > 200 times previous work) • More refined PWA is underway • Status: • Exotic 1-+ p1(1600) has been observed in p-p-p+ channel • The 3p neutral mode shows consistent signals • centrally produced charged 4p analysis is ongoing • p-h, p-hh analysis is ongoing • Analysis with kaonic channels is ongoing • Interesting structures observed in KKp channels New Frontiers in QCD, February 5, 2010

  44. Backup Slides New Frontiers in QCD, February 5, 2010

  45. WAVE SETS IN PWA OF 2004 DATA New Frontiers in QCD, February 5, 2010

  46. 0-+ : p(1800) IN 2004 PWA • Constant width BW for p(1800) • With low mass background New Frontiers in QCD, February 5, 2010

  47. p- multi-g CHANNELS Selection of p- n-g (n=2, n=4) events 1 outgoing negative track with Etrack < 180 GeV n=2 and n=4 good clusters in ECAL1 and ECAL2 Energy balance: 180 < Ep ng<200 GeV assuming the track to be a pion Co-planarity : -0.3 < fpng – fp < 0.3 rad. New Frontiers in QCD, February 5, 2010

  48. THE RICH DETECTOR 3 m 6 m photon detectors 5 m C4F10 • radiator gas: C4F10 • mirror wall: 20 m2 surface • photon-detectors: • outer part (75%) MWPC(pad RO) with CsI cathode • inner part(25%) 576 MAPMTs with indiv. telescope threshold momenta • pp = 2 GeV/c • pK = 9 GeV/c • pP =17 GeV/c Installed in 2005, Used in data taking from 2006 New Frontiers in QCD, February 5, 2010

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