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The JLab 12 GeV Upgrade

The JLab 12 GeV Upgrade. Antje Bruell, JLab PacSpin 2007, Vancouver, Canada. Upgrade of accelerator and experimental equipment Highlights of the physics program @ 12 GeV Highlights of spin dependent measurements @ 12 GeV Timelines and schedule. Jefferson Lab Today.

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The JLab 12 GeV Upgrade

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  1. The JLab 12 GeV Upgrade Antje Bruell, JLab PacSpin 2007, Vancouver, Canada • Upgrade of accelerator and experimental equipment • Highlights of the physics program @ 12 GeV • Highlights of spin dependent measurements @ 12 GeV • Timelines and schedule

  2. Jefferson Lab Today 2000 member international user community engaged in exploring quark-gluon structure of matter Superconducting accelerator provides 100% duty factor beams of unprecedented quality, with energies up to 6 GeV C B A CEBAF’s innovative design allows delivery of beam with unique properties to three experimental halls simultaneously Each of the three halls offers complementary experimental capabilities and allows for large equipment installations to extend scientific reach

  3. Jefferson Lab Today A C B Hall B Hall A Two high-resolution 4 GeV spectrometers Large acceptance spectrometer electron/photon beams Hall C 7 GeV spectrometer, 1.8 GeV spectrometer, large installation experiments

  4. Upgrade magnets and power supplies CHL-2 Enhanced capabilities in existing Halls Lower pass beam energies still available 12 6 GeV CEBAF 11

  5. Experimental equipment for 12 GeV Hall D – exploring origin ofconfinementby studyingexotic mesons Hall B – understandingnucleon structurevia generalized parton distributions Hall C – precision determination ofvalence quarkproperties in nucleons and nuclei Hall A – short range correlations, form factors, hyper-nuclear physics, futurenew experiments

  6. Technical Performance Requirements

  7. Physics Experimental Equipment total project cost: $ 310 M

  8. QCD and confinement Asymptotic Freedom Confinement Small Distance High Energy Large Distance Low Energy Perturbative QCD Strong QCD High Energy Scattering Spectroscopy Gluon Jets Observed Gluonic Degrees of Freedom Missing

  9. Gluonic Excitations Gluonic Excitations • predicted by QCD • crucial for understanding confinement • quantum numbers of the excited gluonic fields couple to those of the quarks to produce mesons with exotic quantum numbers • mass spectra calculated by lattice QCD possibility for experimental search From G. Bali

  10. q q q q Hybrid mesons Hybrid mesons and mass predictions 1 GeV mass difference Normal mesons Jpc = 1-+ Lattice 1-+ 1.9 GeV 2+- 2.1 GeV 0+- 2.3 GeV Lowest mass expected to be p1(1−+) at 1.9±0.2 GeV

  11. Lead Glass Detector Barrel Calorimeter 12 GeV electrons Solenoid Coherent Bremsstrahlung Photon Beam Time of Flight Note that tagger is 80 m upstream of detector Tracking collimated Cerenkov Counter Target GlueX / Hall D Detector Electron Beam from CEBAF

  12. An exotic wave (JPC = 1-+) was generated at level of 2.5 % with 7 other waves. Events were smeared, accepted, passed to PWA fitter. Mass Input: 1600 MeV Width Input: 170 MeV Output: 1598 +/- 3 MeV Statistics shown here correspondto a few days of running. Double-blind M. C. exercise Output: 173 +/- 11 MeV Finding an Exotic Wave

  13. Neutron/Proton Charge Form Factor @12 GeV (Polarization Experiments only) Here shown as ratio of Pauli & Dirac Form Factors F2 and F1, ln2(Q2/L2)Q2F2/F1 constant when taking orbital angular momentum into account (Ji)

  14. Where does the dynamics of the q-q interaction make a transition from the strong (confinement) to the perturbative (QED-like) QCD regime? Charged Pion Electromagnetic Form Factor • It will occur earliest in the simplest systems •  the pion form factor Fp(Q2) provides our best chance to • determine the relevant distance scale experimentally applicability of pQCD (GPD’s) to exclusive pion production ?

  15. Access to the DIS Regime @ 12 GeV with enough luminosity to reach the high-Q2, high-x region! Counts/hour/ (100 MeV)2 (100 MeV2) for L=1035 cm-2 sec-1

  16. Extending DIS to High x The Neutron Asymmetry A1 (similar precision for p and d) The Neutron to Proton Structure Function Ratio Hall C: 3H/3He CLAS: tagging spectator proton 3He(e,e’) 12 GeV will access the valence quark regime (x > 0.3)

  17. Flavor decomposition using SIDIS Valence quarks Ee =11 GeV NH3+He3

  18. Flavor decomposition: polarized sea • Large flavor asymmetry in unpolarized sea • Asymmetry in polarized sea? • First data from HERMES compatible with zero but have large uncertainties • Calculations: • Instantons (QSM) • Pion cloud models ? (Goeke) More data expected from RHIC SSA in future

  19. Beyond form factors and quark distributions – Generalized Parton Distributions(GPDs) X. Ji, D. Mueller, A. Radyushkin (1994-1997) Proton form factors, transverse charge & current densities Structure functions, quark longitudinal momentum & helicity distributions Correlated quark momentum and helicity distributions in transverse space - GPDs

  20. compete with other experiments no overlap with other existing experiments Kinematics for deeply excl. experiments

  21. Q2 = 5.4 GeV2 x = 0.35 -t = 0.3 GeV2 CLAS experiment E0 = 11 GeV Pe = 80% L = 1035 cm-2s-1 Run time: 2000 hrs DVCS: Single Spin Asymmetry DVCS Single-Spin Asymmetry Many x, Q2 and t values measured simultanously !

  22. Projected precision in extraction of GPD H at x = x Spatial Image Projected results

  23. e k' k q' q * p p' orbital angular momentumcarried by quarks : solving thespin puzzle At one value of x only Ingredients: 1) GPD Modeling 2) HERMES 1H(e,e’g)p(transverse target spin asymmetry) 3) Hall A 2H(e,e’gn)p Compared to Lattice QCD For quarks12 GeV will give final answers

  24. r0 Exclusive r0 production on transverse target 2D (Im(AB*))/p T A ~ 2Hu + Hd AUT = - r0 |A|2(1-x2) - |B|2(x2+t/4m2) - Re(AB*)2x2 B ~ 2Eu + Ed AUT A~ Hu - Hd B ~ Eu - Ed r+ Asymmetry depends linearly on the GPDE, which enters Ji’s sum rule. K. Goeke, M.V. Polyakov, M. Vanderhaeghen, 2001 xB

  25. Longitudinally polarized Target SSA for p+ Measurement of kT dependent twist-2 distribution provides an independent test of the Collins fragmentation. Real part of interfe-rence of wave functions with L=0 and L=1 In noncollinear single-hadron fragmentation additional FF H1(z,kT) Efremov et al. p • Study the PT – dependence of AULsin2f • Study the possible effect of large unfavored Collins function. kT quark

  26. Collins AUT ~ Sivers AUT ~ Transverse Target SSA @11 GeV CLAS @ 11GeV (NH3) p+ p0 p- f1T┴, requires final state interactions + interference between different helicity states Simultaneous (with pion SIDIS) measurement of, exclusive r,r+,w with a transversely polarized target important to control the background.

  27. Transversity in double pion production h1 “Collinear” dihadron fragmentation described by two functions at leading twist: D1(z,cosqR,Mpp),H1R(z,cosqR,Mpp) RT quark h2 The angular distribution of two hadrons is sensitive to the spin of the quark • Collins et al, Ji, Jaffe et al, • Radici et al. relative transverse momentum of the two hadrons replaces the PT in single-pion production (No transverse momentum of the pair center of mass involved ) Dihadron production provides an alternative, “background free” access to transversity

  28. JLab 12 x Quark Structure of Nuclei: Origin of the EMC Effect • Observation that structure functions are altered in nuclei stunned much of the HEP community 23 years ago • ~1000 papers on the topic; BUT more data are needed to uniquely identify the origin: What alters the quark momentum in the nucleus? • Jlab at 12 GeV • Precision study of A-dependence • Measurements at x>1 • “Polarized EMC effect” • Flavor-tagged (polarized) structure functions • valence vs. sea contributions

  29. g1(A) – “Polarized EMC Effect” New calculations indicate larger effect for polarized structure function than for unpolarized: scalar field modifies lower components of Dirac wave function Spin-dependent parton distribution functions for nuclei nearly unknown Can take advantage of modern technology for polarized solid targets to perform systematic studies – Dynamic Nuclear Polarization (polarized EMC effect) Curve follows calculation by W. Bentz, I. Cloet, A. W. Thomas.

  30. free nucleon + scalar field + Fermi + vector field (total) DuA(x) DdA(x) Du(x) Dd(x) Duv(x) Ddv(x) x “Polarized EMC Effect” – Flavor Tagging • semi-inclusive DIS on polarized targets, measuring p+ and p-, decompose to extract DuA(x), DdA(x). • Challenging measurement, but have new tools: • High polarization for a wide variety of targets • Large acceptance to constrain syst. errors and tune models Ratios nuclear matter nuclear matter W. Bentz, I. Cloet, A. W. Thomas

  31. APV Measurements APV ~ 8 x 10-5 Q2 0.1 to 100 ppm • Steady progress in technology • part per billion systematic control • 1% normalization control • JLab now takes the lead • New results from HAPPEX • Photocathodes • Polarimetry • Targets • Diagnostics • Counting Electronics E-05-007

  32. DOE Generic Project Timeline We are here DOE CD-2 Reviews September 2007

  33. 12 GeV Upgrade: Phases and Schedule (based on funding guidance provided by DOE-NP in April 2007) • 2004-2005 Conceptual Design (CDR) - finished • 2004-2008 Research and Development (R&D) - ongoing • 2006 Advanced Conceptual Design (ACD) - finished • 2006-2008 Project Engineering & Design (PED) - ongoing • 2009-2013 Construction – starts in ~18 months! • Accelerator shutdown start mid 2012 • Accelerator commissioning mid 2013 • 2013-2015 Pre-Ops (beam commissioning) • Hall commissioning start late 2013

  34. Summary • The Jlab 12 GeV Upgrade will increase the energy of CEBAF, provide very high luminosities and will thus allow to measure with unprecedented precision: • the high x behaviour of (un)polarised structure functions • the spin and flavour decomposition in the valence region • pion and nucleon form factors at high Q2 • single spin asymmetries and kt dependent effects • deep exclusive processes in multi-differential form • nuclear effects in (semi)-inclusive scattering • search for hybrid states • parity violating asymmetries as a test of the standard model • The ideal laboratory for valence quark physics !

  35. Exotic like Flux tube excitation (and parallel quark spins) lead to exotic JPC Quantum Numbers of Hybrid Mesons Excited Flux Tube Quarks Hybrid Meson like

  36. Meson Map qq Mesons Each box corresponds to 4 nonets (2 for L=0) 2 – + Radial excitations 0 – + 2 + + 2.5 Hybrids 2 + – 2 – + 2.0 1 – – Glueballs 1– + exotic nonets 1 + – 1 + + 1.5 0 + – 0 – + 0 + + 1.0 L = 0 1 2 3 4 Mass (GeV) Lattice 1-+ 1.9 GeV 2+- 2.1 GeV 0+- 2.3 GeV (L = qq angular momentum)

  37. Unraveling the Quark WNC Couplings V A A V 12 GeV: (2C2u-C2d)=0.01 PDG: -0.08 ± 0.24 Theory: +0.0986 Vector quark couplings Axial-vector quark couplings

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