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K. Slifer, UNH

E08-027. JLab Readiness Review. K. Slifer, UNH. for the E08-027 Collaboration. May 6, 2011. Inclusive Scattering. 1 st order Feynman diagram. Kinematics. Q 2 : 4-momentum transfer X : Bjorken Scaling var W : Invariant mass of target. ° *. Inclusive Scattering.

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K. Slifer, UNH

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  1. E08-027 JLab Readiness Review K. Slifer, UNH for the E08-027 Collaboration May 6, 2011

  2. Inclusive Scattering 1st order Feynman diagram Kinematics Q2 : 4-momentum transfer X : Bjorken Scaling var W : Invariant mass of target ° *

  3. Inclusive Scattering 1st order Feynman diagram Q2 : 4-momentum transfer X : Bjorken Scaling var W : Invariant mass of target ° * deviation from point-like behavior characterized by the Structure Functions Inclusive Cross Section

  4. Inclusive Scattering When we add spin degrees of freedom to the target and beam, 2 Addiitonal SF needed. ° * Inclusive Polarized Cross Section SFs parameterize everything we don’t know about proton structure

  5. E08-027 : Proton g2 Structure Function A. Camsonne J.P. Chen D. Crabb K. Slifer • Primary Motivation • Proton g2 structure function has never been measured at low or moderate Q2. • We will determine this fundamental quantity at the lowest possible Q2 • This will help to clarify several outstanding puzzles • Hydrogen HyperFine Splitting : Lack of knowledge of g2 at low Q2 is one of the leading uncertainties. • Proton Charge Radius : also one of the leading uncertainties in extraction of <Rp> from m-H Lamb shift.

  6. Measure of QCD complexity Spin Polarizability Systematic uncertainty In Measurements of Ideal place to test ÂPT calcs Structure dependent effects in Q.E.D. Hydrogen Hyperfine Structure Proton Charge Radius SUM Rules Extended GDH SUM BC SUm Rule ELT SUM Rule

  7. Burkhardt Cottingham Sum Rule = 0 predicted to vanish for all Q2

  8. BC Sum Rule 0<x<1 P N BC satisfied w/in errors for Neutron (But just barely in vicinity of Q2=1!) 3He BC satisfied w/in errors for 3He

  9. BC Sum Rule 0<x<1 P BC satisfied w/in errors for JLab Proton 2.8 violation seen in SLAC data N 3He

  10. BC Sum Rule 0<x<1 P BC satisfied w/in errors for JLab Proton 2.8 violation seen in SLAC data Mostly unmeasured N 3He

  11. Spin Polarizabilities Major failure (>8s) of PT for neutron dLT. similar problem for proton g0 this is the region we should start to be able to trust PT

  12. Finite Size Effects • Hydrogen HyperFine Splitting : Lack of knowledge of g2 at low Q2 is one of the leading uncertainties. • Proton Charge Radius : also one of the leading uncertainties in extraction of <Rp> from m-H Lamb shift. The finite size of the nucleon (QCD) plays a small but significant role in calculating atomic energy levels in QED. nucleus ≈ 10-15 Atom ≈ 10-10

  13. Proton Charge Radius from mP lamb shift disagrees with eP scattering result by about 6% <Rp> = 0.84184 ± 0.00067 fm Lamb shift in muonic hydrogen <Rp> = 0.897 ± 0.018 fm World analysis of eP scattering <Rp> = 0.8768 ± 0.0069 fm CODATA world average R. Pohl et.alNature, July 2010 I. Sick PLB, 2003

  14. Polarizability : Integrals of g1 and g2 weighted by 1/Q4 Zemach radius : Integral of GEGM weighted by 1/Q2 Dominated by Kinematic region of E08-027 and E08-007

  15. Experimental Technique P − P

  16. Experimental Technique P P − − P P

  17. Experimental Technique Inclusive Polarized Cross Section differences We Need: Polarized proton target(see talks of C. Keith, D. Crabb) upstream chicane (T. Michalski) downstream local dump (A. Gavalya) Low current polarized beam Upgrades to existing Beam Diagnostics to work at 85 nA (T. Michalski) Lowest possible Q2 in the resonance region Septa Magnets to detect forward scattering (A. Gavalya, E. Folts)

  18. Polarized Ammonia Target 5 Tesla Transverse Field Current = 85 nA

  19. Moller Polarimeter Third arm luminosity monitor for cross-check(not shown). Compton will not be used.

  20. New Beam Diagnostics for low current Slow raster for target

  21. Up Stream Chicane 2 Dipoles to compensate for target field Magnets on loan from Hall C

  22. Low Power Local Dump Mag field of target -> beam will not make it to hall dump

  23. Room Temperature Septum Magnets -Used in Prex, modified with new coils. -bend 5.6o to 12.5o -allow access to lowest possible Q2

  24. Systematic Error Budget Statistical error to be equal or better at all kins

  25. Projected Results Spin Polarizability LT BC Sum Rule

  26. Proposal Kinematics EG4: g1p E08-027 : g2p 0.02 < Q2 < 0.5 GeV2 Resonance Region

  27. Changes from Proposal Room temp septa magnets instead of cryo septa for co-existence with QWeak. leads to a small gap in coverage at large Q2, but the min Q2 is unchanged. requires transition time to remove the septa.

  28. Changes from Proposal Room temp septa magnets instead of cryo septa for co-existence with QWeak. leads to a small gap in coverage at large Q2, but the min Q2 is unchanged. requires transition time to remove the septa. Target field distorts the scattering plane much more than initial estimates. If ignored this would push the Q2 coverage to 0.08 GeV2 instead of 0.02 GeV2

  29. Changes from Proposal Room temp septa magnets instead of cryo septa for co-existence with QWeak. leads to a small gap in coverage at large Q2, but the min Q2 is unchanged. requires transition time to remove the septa. Target field distorts the scattering plane much more than initial estimates. If ignored this would push the Q2 coverage to 0.08 GeV2 instead of 0.02 GeV2 We can address this by: a) Running at 2.5 T for the lowest incident energies. b) Manipulating incident angle of electron beam. c) Moving the target out of the nominal scattering plane. Best combination of these still being evaluated

  30. Bottom Line All the physics proposal goals appear to still be attainable. Net result is a shift of lowest Q2 from 0.02 to 0.03 GeV2 We Plan to finalize run configuration within next few days. None of the configurations under consideration require any new design/construction.

  31. Bottom Line All the physics proposal goals appear to still be attainable. Net result is a shift of lowest Q2 from 0.02 to 0.03 GeV2 We plan to finalize run configuration within next few days. None of the configurations under consideration require any new design/construction. JLab support in dealing with this issue has been phenomenal ! Beamline/Accelerator/Design/Installation/Target

  32. run the two lowest energies with only 2.5 T target field & Elevate the target 9 cm above nominal scattering plane.

  33. run the two lowest energies with only 2.5 T target field & Elevate the target 9 cm above nominal scattering plane.

  34. run the two lowest energies with only 2.5 T target field & Elevate the target 9 cm above nominal scattering plane. reach Q2 = 0.03 GeV2 but 2.5T => PT = 40%

  35. run the two lowest energies with only 2.5 T target field & Elevate the target 9 cm above nominal scattering plane. reach Q2 = 0.03 GeV2 but 2.5T => PT = 40% can regain some stat by changing from 0.5 cm target to 3 cm. still will need to cut some settings

  36. Rates / Schedule

  37. Optimizing Runplan in Progress This is the most recent “Least-painful” choice of settings Large W kinematics are typically the most time consuming so they’ve been trimmed.

  38. Draft Schedule

  39. g2p Runplan SEPTA IN SEPTA OUT

  40. g2p Runplan 1.7 GeV incompatible with Qweak

  41. g2p Runplan Beam Allocation is 87 days + 21 commissioning, so we still have some cutting to do.

  42. g2p Runplan Beam Allocation is 87 days + 21 commissioning, so we still have some cutting to do. We expect to find some saving in optimizing the overhead between g2p and GEp Increasing DAQ rate from 4-8 kHz can save us about 7 calendar days.

  43. Thank you to the committee

  44. Backups

  45. Physics Manpower Post-Docs (Full-time effort) Kalyan Allada (Hall A) : Beamline, 3rd arm Luminosity monitor. James Maxwell (UNH) : Target Expert, SANE veteran, Spin-Physics. Jixie Zhang (Hall A) : Geant4 simulations, Optics. Post-Docs (Part-time effort) Hovhannes Baghdasaryan (UVa) Narbe Kalantarians(UVa) Sarah Phillips (UNH) Xiaohui Zhan (Argonne) This is a Partial list: More details in JP and Ron’s talks

  46. Physics Manpower Graduate Students Tobias Badman (UNH, Slifer): 2nd year, onsite starting June 1. Melissa Cummings (W&M, Todd Averett), 2nd year, onsite from May 1. Chao Gu (UVa, Nilanga Liyanaga), 2nd year, onsite. Min Huang (Duke, Haiyan Gao), 3rd year, onsite, (simulation, optics). Pengjia Zhu (USTC, Yunxiu Ye), 3rd year, onsite, (beamline, target). Ryan Zielinski (UNH, Slifer) : onsite starting June 1. Further expected A student from Temple (Zein-Eddine Meziani), 2nd year, onsite from May 1? E08-007 expects 2 further students (Rutgers and HUJI). This is a Partial list: More details in JP and Ron’s talks

  47. Physics Manpower Faculty and Staff Jian-Ping Chen (JLab) : Project manager, overall coordination. Alexandre Camsonne (JLab): Beam line, DAQ, … Don Crabb (UVA) : Target Expert. Karl Slifer : onsite fulltime summer and fall. onsite fullttime every other week in spring. *For these slides, I’m not counting E08-007 manpower Guy Ron, Doug Higinbotham, Ron Gilman, Donal Day, John Arrington, Adam Sarty...... This is a Partial list: More details in JP and Ron’s talks

  48. Contribution to Hyperfine Splitting

  49. Out of plane scattering angle The 5T magnet field distorts the scattering plane much more than initial simulations revealed, especially at low momentum Effect discovered by Jixie Zhang (Geant4). confirmed by Min Huang (Snake), John Lerose

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