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Introduction 2

Introduction 2. Searching for QCD Exotics with Photon Beams. The Hall D Project. Alex R. Dzierba Indiana University Spokesman Hall D Collaboration. References. Sept/Oct, 2000. Sept, 2000. The Hall D Project Design Report Ver 3. The search for QCD exotics. November, 2000.

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Introduction 2

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  1. Introduction 2 Searching for QCD Exotics with Photon Beams The Hall D Project Alex R. Dzierba Indiana University Spokesman Hall D Collaboration http://dustbunny.physics.indiana.edu/HallD

  2. References Sept/Oct, 2000 Sept, 2000 The Hall D Project Design Report Ver 3 The search for QCD exotics November, 2000 Mapping quark confinement by exotic particles http://dustbunny.physics.indiana.edu/HallD

  3. Outline QCD exotics, gluonic excitations & confinement The experimental evidence for gluonic excitations Why photoproduction? How to identify exotics Partial Wave Analysis (PWA) What is needed Experimental technique Collaboration and project status Conclusion http://dustbunny.physics.indiana.edu/HallD

  4. QCD and confinement Spectroscopy High Energy Scattering Gluon Jets Observed Gluonic Degrees of Freedom Missing Asymptotic Freedom Confinement Small Distance High Energy Large Distance Low Energy Non-Perturbative Regime Perturbative Regime http://dustbunny.physics.indiana.edu/HallD

  5. Flux Tubes Flux Tubes & Confinement Color Field: Because of self interaction, confining flux tubes form between static color charges Notion of flux tubes comes about from model-independent general considerations. Idea originated with Nambu in the ‘70s http://dustbunny.physics.indiana.edu/HallD

  6. Early Flux Tubes http://dustbunny.physics.indiana.edu/HallD

  7. Lattice QCD Flux tubes realized Confinement arises from flux tubes andtheir excitation leads to a new spectrum of mesons http://dustbunny.physics.indiana.edu/HallD

  8. Normal Mesons q q Not allowed: exotic combinations: q q JPC = 0+- 1-+ 2+- … Normal mesons occur when the flux tube is in its ground state Spin/angular momentum configurations & radial excitations generate our know spectrum of light quark mesons Nonets characterized by given JPC http://dustbunny.physics.indiana.edu/HallD

  9. Excited Flux Tubes First excited state of flux tube has J=1 and when combined with S=1 for quarks generate: q q JPC = 0-+ 0+-1+- 1-+2-+ 2+- exotic q q Exotic mesons are not generated when S=0 How do we look for gluonic degrees of freedom in spectroscopy? http://dustbunny.physics.indiana.edu/HallD

  10. Meson Map qq Mesons Each box corresponds to 4 nonets (2 for L=0) Radial excitations Mass (GeV) Glueballs Hybrids 2.5 2.0 1.5 1.0 L = 0 1 2 3 4 http://dustbunny.physics.indiana.edu/HallD

  11. Meson Map1 qq Mesons Mass (GeV) JPC = 0-+ Glueballs Hybrids 2.5 2.0 JPC = 1-- 1.5 1.0 L = 0 1 2 3 4 http://dustbunny.physics.indiana.edu/HallD

  12. Meson Map-2 qq Mesons Mass (GeV) 2 – + Glueballs 0 – + 2 + + Hybrids 2.5 2 + – 2 – + 1 – – 2.0 1– + exotics 1 + – 1 + + 1.5 0 + – 0 – + 0 + + 1.0 L = 0 1 2 3 4 http://dustbunny.physics.indiana.edu/HallD

  13. Current Evidence Have gluonic excitations been observed ? Glueballs Hybrids Overpopulation of the scalar nonet and LGT predictions suggest that the f0(1500) is a glueball JPC = 1-+ states reported 1(1400)  1(1600)  See results from Crystal Barrel See results from BNL E852 Complication is mixing with conventional qq states Not without controversy http://dustbunny.physics.indiana.edu/HallD

  14. Crystal barrel Crystal Barrel Evidence for fo(1500) http://dustbunny.physics.indiana.edu/HallD

  15. Crystal Barrel - II Crystal Barrel Low Statistics http://dustbunny.physics.indiana.edu/HallD

  16. Why photoproduction ? S = 0 before before after after  Much data in hand but not overwhelming evidence for gluonic excitations beam q q q q  beam Almost no data on in the mass region where we expect to find exotic hybrids when flux tube is excited q q q q p and  really are different probes S = 1 A meson beam when scattering occurs can have its flux tube excited http://dustbunny.physics.indiana.edu/HallD

  17. Compare pion and Photoproduction Data @ 19 GeV 28 Events/50 MeV SLAC SLAC 4 Compare statistics and shapes @ 18 GeV BNL http://dustbunny.physics.indiana.edu/HallD

  18. Partial Wave Analysis (PWA) Line shape and phase consistent with Breit-Wigner line shape production Low t C.M.S. A simple example - identifying states which decay into pp Production and decay point the way Decay into pp implies J=L, P=(-1)L and C=(-1)L http://dustbunny.physics.indiana.edu/HallD

  19. Decay Angular Distributions C.M.S. JPC=1-- JPC=2++ JPC=3-- http://dustbunny.physics.indiana.edu/HallD

  20. E852 Results @ 18 GeV Decompose this http://dustbunny.physics.indiana.edu/HallD

  21. Results of PWA And the exotic http://dustbunny.physics.indiana.edu/HallD

  22. An Exotic Signal in E852 Correlation of Phase & Intensity Mass (GeV) Leakage From Non-exotic Wave Exotic Signal Mass (GeV) http://dustbunny.physics.indiana.edu/HallD

  23. Hybrid Decays Gluonic excitations transfer angular momentum in their decays not to the relative angular momentum of meson pairs but to the internal orbital angular momentum of the qq pairs. Favored: X[1-+]  Sqq + Pqq NotFavored: X[1-+]  Sqq + Sqq We want to determine this and be sensitive to a wide variety of decay modes to test models and to certify the PWA. http://dustbunny.physics.indiana.edu/HallD

  24. What is Needed? • PWA requires that the entire event be identified - all particles • detected, measured and identified. The detector should be hermetic with excellent resolution and capability of identifying photons and p from K from protons. • The beam energy should be sufficiently high to produce mesons in the • desired mass range with sufficient acceptance. Too high an energy will introduce backgrounds, reduce many cross-sections of interest and make it difficult to achieve above experimental goals. • PWA also requires high statistics and linearly polarized photons. Linear polarization will be discussed. At 107 photons/sec and a 30-cm LH2 target a 1 µb cross-section will yield 60M events/yr. This would about 1M exotics in a given channel. http://dustbunny.physics.indiana.edu/HallD

  25. Optimal Photon Energy Electron endpoint energy of 12 GeV relative yield Figure of merit based on: Beam flux and polarization Production yields Separation of meson/baryon production M[x] is produced meson mass http://dustbunny.physics.indiana.edu/HallD

  26. Electron Beam Energy Electron energy Photon energy http://dustbunny.physics.indiana.edu/HallD

  27. Linear Polarization - I For circular polarization For linear polarization V Suppose we produce a vector via exchange of spin 0 particle and then V  SS J=0 Loss in degree of polarization requires corresponding increase in stats http://dustbunny.physics.indiana.edu/HallD

  28. Linear Polarization - II With linear polarization which is sum or diff of R and L we can separate Linear Polarization Essential Parity conservation implies: V X J=0– or 0+ Suppose we want to determine exchange: O+ from 0- or AN from AU http://dustbunny.physics.indiana.edu/HallD

  29. Hall D at JLab http://dustbunny.physics.indiana.edu/HallD

  30. Detector Lead Glass Detector Barrel Calorimeter Solenoid Coherent Bremsstrahlung Photon Beam Time of Flight Tracking Cerenkov Counter Target Electron Beam from CEBAF http://dustbunny.physics.indiana.edu/HallD

  31. Photon Beam Collimation enhances coherent over incoherent component Flux Photon beam energy (GeV) Coherent bremsstrahlung will deliver the necessary Polarization, energy and flux concentrated in the region of interest Coherent and incoherent spectrum For 15 micron diamond radiator http://dustbunny.physics.indiana.edu/HallD

  32. Solenoid Superconducting Solenoid Built at SLAC for LASS Now at LANL - used in MEGA At LANL Central field: 2.5 T At SLAC http://dustbunny.physics.indiana.edu/HallD

  33. LGD Built by the Indiana Group for BNL Exp 852 3000 PbO blocks PM’s/ADC’s Transferred to JLab July, 2000 http://dustbunny.physics.indiana.edu/HallD

  34. Phi experiment Phi decays Rare Radiative Decays of the f meson Events/10 MeV Cut-away of Radphi Detector located in Hall B http://dustbunny.physics.indiana.edu/HallD

  35. Acceptance Gottfried-Jackson frame: Acceptance in In the rest frame of X Mass [X] = 1.4 GeV the decay angles are Mass [X] = 1.7 GeV Decay Angles theta, phi Mass [X] = 2.0 GeV assuming 8 GeV photon beam http://dustbunny.physics.indiana.edu/HallD

  36. Monte Carlo PWA Exotic wave PWA Exercise Events were generated, smeared and passed to PWA fitter. 0.8% 7.5% The Mix: L between r and  resonance 88% 1.5% The % refer to the fraction of the wave in the original data set. Errors correspond to about 1 day’s running http://dustbunny.physics.indiana.edu/HallD

  37. Finding the Exotic Wave Mass Input: 1600 MeV Output: 1598 +/- 3 MeV Width Input: 170 MeV Output: 173 +/- 11 MeV PWA Exercise PC The J exotic was in the mix with other waves at the level of 2.5% The generated mass and width are compared with those from PWA fits: Events/20 MeV Mass (GeV) http://dustbunny.physics.indiana.edu/HallD

  38. Collaboration - I Collaboration Board L. Dennis (FSU) R. Jones (U Conn) J. Kellie (Glasgow) A. Klein (ODU) G. Lolos (Regina) (chair) A. Szczepaniak (IU) Alex Dzierba (Spokesperson) - IU Curtis Meyer (Deputy Co-Spokesperson) - CMU Elton Smith (JLab Hall D Group Leader) R. Clark, P. Eugenio, G. Franklin, C. A. Meyer, B. Quinn, R. Schumacher [Carnegie Mellon University] H. Crannel, D. Sober [Catholic University of America] US Experimental Groups D. Doughty, D. Heddle [Christopher Newport University] R. Jones [University of Connecticut] W. Boeglin, L. Kramer, P. Markowitz, B. Raue, J. Reinhold [Florida International University] L. Dennis, R. Dragovitsch, G. Riccardi [Florida State University] A, Dzierba, R. Heinz, E. Scott, P. Smith, C. Steffen, T. Sulanke, S. Teige [Indiana University] D. Abbott, I. Bird, R. Carlini, H. Fenker, G. Heyes, C. Sinclair, E. Smith, D. Weygand, E. Wolin [JLab] R. Mischke, A. Palounek, J-C Peng [Los Alamos National Lab] M. Khandaker, V. Punjabi, C. Salgado [Norfolk State University] G. Dodge, A. Klein, S. Kuhn, P. Ulmer, L. Weinstein [Old Dominion University] D. Carman, K. Hicks [Ohio University] S. Dytman, J. Mueller [University of Pittsburgh] G. Adams, J. Cummings, A. Empl, J. Napolitano, P. Stoler [Renssalaer Polytechnic Institute] http://dustbunny.physics.indiana.edu/HallD

  39. Collaboration - II Experimental Groups outside the US J. Annand, I. Anthony, D. Ireland, J. Kellie, K. Livingston, D. MacGregor, C. McGeorge, B. Owens, G. Rosner, D. Watts [U. of Glasgow - Scotland] S. Denisov, N.Fedyakin, A. Gorokhov, V. Samoilenko, A. Schukin [Institute for HEP - Protvino] V. A. Bodyagin, A. M. Gribushin, N. A. Kruglov, V. L. Korotkikh, M. A. Kostin, A. I. Demianov, O. L. Kodolova, L. I. Sarycheva, A. A. Yershov [Moscow State University] V. Druginin, V. Ivanchenko, E. Solodov [Budker Institute - Novosibirsk] E. J. Brash, G. M. Huber, G. J. Lolos, Z. Papandreou [University of Regina] Theory Group • D. Leinweber, W. Melnitchouk, A. Thomas, A. Wiliams [CSSM & University of Adelaide] • S. Gofrey [Carleton University] • R. Kaminski, L. Lesniak [Henryk Niewodniczanski Institute of Nuclear Physics- Cracow] • J. Goity [Hampton University] • C. Horowitz, T. Londergan, M. Pichowski, A. Szczepaniak, C. Wolfe [Indiana University] • P. Page [Los Alamos] • A. Afanasev [North Carolina Central University] • E. Swanson [University of Pittsburgh] • T. Barnes [University of Tennessee/Oak Ridge] • R. Davidson [Rensselaer Polytechnic Institute ] http://dustbunny.physics.indiana.edu/HallD

  40. Review The Committee David Cassel Cornell (chair) Frank Close Rutherford John Domingo JLab Bill Dunwoodie SLAC Don Geesaman Argonne David Hitlin Caltech Martin Olsson Wisconsin Glenn Young ORNL Project Reviewed Dec, 1999 Executive Summary Highlights: • The experimental program proposed in the Hall D Project is well-suited for definitive searches of • exotic states that are required according to our current understanding of QCD • JLab is uniquely suited to carry out this program of searching for exotic states • The basic approach advocated by the Hall D Collaboration is sound • The collaboration will be ready to begin work on a Conceptual Design Report once a • Project Office with Project Director is in place • An R&D program is required to ensure that the magnet is usable, to optimize many of the detector • choices, to ensure that novel designs are feasible and to validate cost estimates. http://dustbunny.physics.indiana.edu/HallD

  41. Conclusions Role of glue in strong QCD is needed foran understanding of confinement Physics Unambiguous identification of gluonic excitations will start with exotic hybrids Goal Exotic hybrids are expected precisely where there is little experimental information Photoproduction Flux, duty factor, energy & polarization available at an energy upgraded CEBAF & and JLab is unique Beams Detector is state of the art & based on several existing subsystems and will yield excellent coverage, resolution & unprecedented statistics Detector http://dustbunny.physics.indiana.edu/HallD

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