Introduction 2 Alex R. Dzierba Indiana University Spokesman Hall D Collaboration Searching for QCD Exotics with.

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

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

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

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

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

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

http://dustbunny.physics.indiana.edu/HallD Normal Mesons 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 J PC Not allowed: exotic combinations: J PC = 0 +- 1 -+ 2 +- … q q q q

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

http://dustbunny.physics.indiana.edu/HallD Meson Map Glueballs Hybrids Mass (GeV) 1.0 1.5 2.0 2.5 qq Mesons L = 01234 Each box corresponds to 4 nonets (2 for L=0) Radial excitations

http://dustbunny.physics.indiana.edu/HallD Meson Map 1 Glueballs Hybrids Mass (GeV) 1.0 1.5 2.0 2.5 qq Mesons L = 01234 J PC = 1 -- J PC = 0 -+

http://dustbunny.physics.indiana.edu/HallD Meson Map-2 exotics 0 – + 0 + – 1 + + 1 + – 1 – + 1 – – 2 – + 2 + – 2 + + 0 – + 2 – + 0 + + Glueballs Hybrids Mass (GeV) 1.0 1.5 2.0 2.5 qq Mesons L = 01234

http://dustbunny.physics.indiana.edu/HallD Current Evidence GlueballsHybrids Overpopulation of the scalar nonet and LGT predictions suggest that the f 0 (1500) is a glueball See results from Crystal Barrel J PC = 1 -+ states reported  1 (1400)   1 (1600)  See results from BNL E852 Complication is mixing with conventional qq states Not without controversy Have gluonic excitations been observed ?

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

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

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

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

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

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

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

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

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

http://dustbunny.physics.indiana.edu/HallD 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 -+ ]  S qq + P qq NotFavored: X[1 -+ ]  S qq + S qq 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 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  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 10 7 photons/sec and a 30-cm LH 2 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 Optimal Photon Energy Figure of merit based on: 1.Beam flux and polarization 2.Production yields 3.Separation of meson/baryon production Electron endpoint energy of 12 GeV M[x] is produced meson mass relative yield

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

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

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

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

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

http://dustbunny.physics.indiana.edu/HallD Photon Beam Photon beam energy (GeV) Flux 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 Collimation enhances coherent over incoherent component

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

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

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

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

http://dustbunny.physics.indiana.edu/HallD Finding the Exotic Wave The J PC 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: Mass Input: 1600 MeV Width Input: 170 MeV Output: 1598 +/- 3 MeV Output: 173 +/- 11 MeV Mass (GeV) Events/20 MeV

http://dustbunny.physics.indiana.edu/HallD Collaboration - I US Experimental Groups Alex Dzierba (Spokesperson) - IU Curtis Meyer (Deputy Co-Spokesperson) - CMU Elton Smith (JLab Hall D Group Leader) L. Dennis (FSU)R. Jones (U Conn) J. Kellie (Glasgow)A. Klein (ODU) G. Lolos (Regina) (chair)A. Szczepaniak (IU) Collaboration Board R. Clark, P. Eugenio, G. Franklin, C. A. Meyer, B. Quinn, R. Schumacher [Carnegie Mellon University] H. Crannel, D. Sober [Catholic University of America] 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 Collaboration - II oD. Leinweber, W. Melnitchouk, A. Thomas, A. Wiliams [CSSM & University of Adelaide] oS. Gofrey [Carleton University] oR. Kaminski, L. Lesniak [Henryk Niewodniczanski Institute of Nuclear Physics- Cracow] oJ. Goity [Hampton University] oC. Horowitz, T. Londergan, M. Pichowski, A. Szczepaniak, C. Wolfe [Indiana University] oP. Page [Los Alamos] oA. Afanasev [North Carolina Central University] oE. Swanson [University of Pittsburgh] oT. Barnes [University of Tennessee/Oak Ridge] oR. Davidson [Rensselaer Polytechnic Institute ] 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] Experimental Groups outside the US Theory Group

http://dustbunny.physics.indiana.edu/HallD Review David CasselCornell (chair) Frank CloseRutherford John DomingoJLab Bill DunwoodieSLAC Don GeesamanArgonne David HitlinCaltech Martin OlssonWisconsin Glenn YoungORNL The Committee 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 Conclusions Role of glue in strong QCD is needed for an understanding of confinement Physics Unambiguous identification of gluonic excitations will start with exotic hybrids Goal 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 Exotic hybrids are expected precisely where there is little experimental information Photoproduction

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Introduction 2 Alex R. Dzierba Indiana University Spokesman Hall D Collaboration Searching for QCD Exotics with.

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