The GlueX Project at Jefferson Lab G. Bali D. Leinweber Zisis Papandreou GlueX Collaboration University of Regina, Canada Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 1

100 Physicists 27 Institutions 6 Countries Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 2

12 GeV/GlueX Project Update 2004/03: CD-0 (mission need) 2005/04: Scientific Review by ONP, “the scientific opportunity afforded by the 12 GeV upgrade is outstanding, … in studies of QCD and the quark structure of matter” 2006/02: CD-1 (Preliminary Baseline Range) 2006/08: PAC Proposals for 12 GeV 2007/12: CD-2 (Performance Baseline) 2008/12: CD-3 (Construction Start) 2013: Beam delivery? 2015: CD-4 (Start of Operations/Closeout) Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 3

GlueX Music Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 4

Asymptotic Freedom Confinement QCD and confinement 3-Jet g Perturbative Non-Perturbative Asymptotic Freedom Confinement Small Distance High Energy Large Distance Low Energy High Energy Scattering Gluon Jets Observed 3-Jet Spectroscopy Gluonic Degrees of Freedom Missing g Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 5

Strong QCD in quark pairs and triplets white Nominally, glue is not needed to describe hadrons. Allowed systems: gg, ggg, qqg, qqqq Glueballs Hybrids Molecules _ Gluonic Excitations GlueX Focus: “light-quark mesons” u d s c b t Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 6

Flux tubes realized in LQCD Fun on the Lattice Color Field: Gluons possess color charge: they couple to each other! Flux tubes realized in LQCD linear potential 0.4 0.8 1.2 1.6 1.0 2.0 0.0 Vo( r) [GeV] r (fm) D. Leinweber G. Bali Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 7

How do we look for gluonic degrees of freedom in spectroscopy? “Pluck” the Flux Tube How do we look for gluonic degrees of freedom in spectroscopy? Hybrid meson: flux tube in excited state m=1 CP=(-1) S In the first-excited state we have two degenerate transverse modes with J=1 – clockwise and counter-clockwise – and their linear combinations lead to JPC = 1– + or JPC=1+ – for the excited flux-tube Normal meson: flux tube in ground state m=0 CP=(-1) S+1 Nonets characterized by given JPC Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 8

Meson Map exotic nonets - 2 + – 2 + + 2 – + 1 – – 1– + 1 + – 1 + + Each box corresponds to 4 nonets (2 for L=0) qq Mesons Mass (GeV) exotic nonets 0 – + 0 + – 1 + + 1 + – 1– + 1 – – 2 – + 2 + – 2 + + 0 + + Glueballs Hybrids Radial excitations 2.5 2.0 1.5 Ordering of the hybrids is a QN ordering Note vertical labels LQCD 0++ 1.6 GeV 1-+ 1.9 GeV 1.0 - L = 0 1 2 3 4 (L = qq angular momentum) Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 9

Production of Hybrid Mesons Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 10

Evidence for Exotic Hybrids Much data in hand (exotic hybrids are suppressed)  or beam q after Quark spins anti-aligned Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 11

Partial Wave Analysis (PWA) Bump hunting in cross section data is inadequate to the task Need PWA: Identify the JPC of a meson Determine production amplitudes & mechanisms Include polarization of beam, target, spin and parity of resonances and daughters, relative angular momentum. GlueX experience: E852, Crystal Barrel, CLAS; new independent code being developed Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 12

Photocouplings & Phenomenology g beam q after Couplings virtually unknown even for conventional mesons Testbed: by the time GlueX runs expect all predictions to be tested by Lattice QCD Quark spins aligned Phenomenology: isobar model widely used in multi-particle N N states; it is not completely general factorized approach has limitations: e.g. Deck effect where we get threshold peak in isobar  S-wave Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 13

Scientific Goals and Means Definitive and detailed mapping of hybrid meson spectrum Search for smoking gun signature of exotic JPC hybrid mesons; these do not mix with qq states ss and baryon spectroscopy, … Tools for the GlueX Project: Accelerator: 12 GeV electrons, 9 GeV tagged, linearly polarized photons with high flux Detector: hermiticity, resolution, charged and neutrals PWA Analysis: spin-amplitude of multi-particle final states Computing power: 1 Pb/year data collection, databases, distributed computing, grid services… - - Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 14

Upgrade magnets and power supplies 12 11 6 GeV CEBAF Upgrade magnets and power supplies CHL-2 Two 0.6 GeV linacs 1.1 help me Beam Power: 1MW Beam Current 5 µA Emittance: 10 nm-rad Energy Spread: 0.02% Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 15

Ideal Photon Beam Energy Figure of Merit: - Start with 12 GeV electrons Meson yield for high mass region Separate meson from baryon resonances Balance beam flux/polarization Coherent bremsstrahlung, tagger, collimator Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 16

GlueX Detector Design is mature: Magnet: Beam tests: based on 7 years of R&D on subsystems ideally matched to 9 GeV photon beam Magnet: 2 Tesla superconducting solenoid Beam tests: - BCAL, FDC, TOF Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 17

Tracking Subsystems Cylindrical Drift Chamber 25 radial layers of tubes 17 straight layers 4 +6o stereo layers 4 -6o stereo layers dE/dx for p· 450 MeV/c ~3200 channels r~ 150 m, z~2 mm Forward Drift Chamber 4 identical packages 24 layers of tubes Cathode/wire/cathode U&V strip planes ~12000 channels 200 m resolution Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 18

Forward and Rear Calorimeters Forward Calorimeter (LGD) 4x4cm2 lead glass blocks (used in E852 and RadPhi) ~2800 channels /E=7.3%/E + 3.6% TOF Scintillator Wall 250x6x2.54 cm3 bars ~168 channels  = sub 100ps Upsteam Veto Calorimeter Lead/scintillator based 18 layers of scintillator 56 238x4.25cm2 U, V layers 8.9X0, 24% sampl. fraction ~ few hundred channels Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 19

Decay Photon Distributions Detecting ’s and ’s is essential for GlueX Pythia simulations 28% of photons in FCAL 70% of decay photons are captured by BCAL 50% of BCAL ones have energies < 300MeV BCAL has a large workload FCAL-BCAL handoff (100-120) important Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 20

Module Construction - 0.5 mm lead sheets 1mm scintillating fibers optical epoxy 210 layers BCAL design modeled after KLOE EMC; Our thanks to INFN Frascati & Pisa Groups! Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 21

 Barrel Calorimeter (0 or  decay) 48 modules (phi sectors) Outer Layers Outer layers (10cm depth): 2x2 array PMTs: 384 units  Inner Layers Inner layers (12cm depth): 4x6 array SiPMs: 2304 units (0 or  decay) - X0 = 1.45cm Sampling Fraction = 11% Prelim. /E=5.4%/E  1.5% Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 22

SiPM Prototype Components Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 23

SiPM Device Packaging SA - IV Curve 5 Phase-1 Prototypes On glass Ultrasonic bond - shear, flex absorption Thermocompression bond - warping of flex, process 5 Phase-1 Prototypes On glass SA - IV Curve Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 24

Physics Plans  Detector commissioning Physics commissioning: density matrices, a2(1320) Exotic hybrid search  ss physics, baryon spectroscopy, … Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 25

Summary We welcome new collaborators! The nature of confinement is an outstanding and fundamental question of quarks and gluons in QCD. Lattice QCD and phenomenology strongly indicate that the gluonic field between quarks forms flux-tubes and that these are responsible for confinement. The excitation of the gluonic field leads to an entirely new spectrum of mesons and their properties are predicted by lattice QCD. Data are needed to validate these predictions. PWA and improved theoretical understanding is required. The definitive experiment for this search will be GlueX at the energy-upgraded JLab. If exotic hybrids are there, we will find them! We welcome new collaborators! Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 26

References/Acknowledgments G. Bali, U. Glasgow D. Leinweber, CSSM / U. Adelaide A. Dzierba, U. Indiana C. Meyer, CMU J. Dudek, JLab portal.gluex.org www.halld.org www.gluex.org Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 27

Backup Slides Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 28

Coherent Bremsstrahlung 12 GeV electrons Incoherent & coherent spectrum flux This technique provides requisite energy, flux and polarization tagged with 0.1% resolution 40% polarization in peak photons out collimated electrons in 40 % polarization - truncate 1t 11.5 GeV - Note the discussion about upper energy spectrometer diamond crystal photon energy (GeV) Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 29

Linear Polarization Linear polarization is: Essential to isolate the production mechanism (M) if X is known A JPC filter if M is known (via a kinematic cut) Degree of polarization is directly related to required statistics Linear polarization separates natural and unnatural parity States of linear polarization are eigenstates of parity. States of circular polarization are not. Remove checkmarks Work with Adam on re-word M Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 30

Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 31

Fiber Spectra Two-step process: absorption and re-emission of light due to dopants 420nm 490nm Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 32

Silicon PM Packaging Currently: A35H chip Pixel: independent photon micro-counter in limited Geiger mode Breakdown bias: 25-30V Gain: >106 4496 pixels PDE=5.5% 6744 pixels PDE=10.5% Currently: A35H chip Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 33

PE Spectrum Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 34

PE Spectrum Reduction in DR Dark Current - Dominated by single-pixel thermal carrier events - Causes shifts in pedestals based on E and no of readout cells fired Reduction in DR - Optical isolation (trenching) - Cooling - Threshold over 1pe - V+ relaxation Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 35

Device Coupling Z, Papandreou, U of Regina Winston Cone Emission Facet Z, Papandreou, U of Regina Hadron 2007, Frascati, October 11, 2007 36