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High-Q2 Deuteron Experiment Analysis at Old Dominion University

Investigating the deuteron through experiments focusing on deep inelastic scattering, wavefunctions, and final state interactions. Analysis results include VDC tracking studies, target density evaluations, and beam energy shift measurements. Preliminary physics results show promising data and challenges for the future.

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High-Q2 Deuteron Experiment Analysis at Old Dominion University

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  1. Experiment E01-020(e,e'p) Studies of the Deuteron at High Q2 P.E. Ulmer Old Dominion University Spokespersons: W. Boeglin, M. Jones, A. Klein, P. Ulmer and E. Voutier Postdoc: R. Roché Graduate Students: L. Coman and H. Ibrahim

  2. Outline • Physics Motivation • Some Analysis Results • VDC tracking • Target density studies • Beam position studies • Beam energy shifts • Preliminary Physics Results

  3. Physics Motivation

  4. Physics Motivation Overview Elastic Deep Inelastic  Quasielastic N*  Wavefunction (parallel kin) RLT (relativity) (perpendicular kin) MECs/ICs (parallel kin) FSI (neutron angular distribution) Kinematics: Q2=0.8, 2.1, 3.5 GeV2 Pmiss = 0-500 MeV/c

  5. RLT and Relativity • Relativistic current operator • Longitudinal piece contains additional spin- orbit term • Can interfere with spin-flip magnetization term in transverse current • Non-relativistically, get no such contribution since L reflects charge only and can’t interfere with spin-flip part of T: different final states

  6. RLT (projected uncertainties)

  7. Final State Interactions

  8. Eikonal Approximation • FSI described as sequential multiple scatterings • , b impact parameter • successfully used in hadron scattering • for nucleons at rest  Glauber approximation • for moving nucleons  Generalized Eikonal Approximation (GEA, Sargsian), Generalized Glauber Approximation (GGA, Ciofi degli Atti), Relativistic Multiple Scattering Glauber Approximation (RMSGA, Ryckebusch)

  9. Some Analysis Results

  10. Analysis Overview

  11. VDCs

  12. z VDC U1 two-cluster intersection cluster 1 cluster 2 z = 0 z-inter Spectrometer exit window

  13. u1 v1 z-coordinate of intersection of tracks for two clusters Exit window # Events Left Arm z relative to each VDC plane (m)

  14. Transverse dimension: Left Arm -8.6 cm +9.2 cm Positions taken from Gaussian fits (not shown). Distance between peaks: 17.8 cm Width of exit window: 17.1 cm Y for 2 cluster intersection (using u1 and v1) (meters)

  15. Event Display (R. Roché)

  16. Target Density

  17. Cuts: -4<εm<10 MeV 3mult7 clusters=1 Corrections: T5/E5 no VDC corr. LH2 Boiling: 15 cm cigar cell Raster: 2mm x 2mm nominal, Fan: 60Hz 23.3% at 100 μA! Events/charge (arb. Units) PRELIMINARY Beam Current (μA)

  18. LD2 Boiling: ~9% variation / 100 uA2mm x 2mm raster

  19. LD2 Boiling: ~4% variation / 100 uA4mm x 4mm raster

  20. Beam Position

  21. Beam Position(Reactz vs. BeamX for foil & raster) Right Arm Left Arm

  22. Reactz vs. BeamX BeamX Scaled by Factor of 1.3 Left Arm Right Arm

  23. Beam Energy

  24. Beam Energy Shifts 0.5 MeV 2 MeV Q2=0.8 GeV2 Q2=2.1 GeV2

  25. 1H(e,e'p) Missing Energy Emiss (MeV) Emiss (MeV) Using Arc Energy (2843.6 MeV) Using Tiefenbach Energy

  26. Physics (Preliminary) Results

  27. Preliminary Results Q2 = 2.1 (GeV/c)2 Q2 = 3.5 (GeV/c)2 FSI/PWIA FSI/PWIA nq nq Calculation J.M. Laget

  28. Summary • Lessons learned • Always use hardware collimators in HRS • Never use cigar cell targets • Watch beam energy carefully • Main hurdles ahead • VDC tracking efficiency • Target boiling studies • Absolute normalizations • Status • First post-running analysis pass nearly complete • Expect preliminary cross sections in few months

  29. Credits Thanks to Werner Boeglin, Luminita Coman and Hassan Ibrahim for help with this talk.

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