Studies of the Deuteron at High Four-Momentum Transfer

1
Studies of the Deuteron at High Q2
(E01-020 Update)
Hassan Ibrahim Old Dominion University (for the
E01-020 Collaboration) Hall A Collaboration
Meeting June 22, 2006 Spokespersons W.
Boeglin, M. Jones, A. Klein, P. Ulmer and E.
Voutier Graduate Students L. Coman and H.
Ibrahim
2
Hall A at Jefferson Lab
E01-020
3
Reaction Kinematics
e'
Scattering Plane
qe
e
p
q
f
qnq
Reaction Plane
n
4
Plane Wave Impulse Approximation and Beyond
n
p
p
n
FSI
PWIA
e'
e'
p''
n'
q
q
e
p'
p'
e
d
d
p
n
MEC
p
n
IC
e'
e'
n'
q
n'
q
e
p'
e
p'
d
d
5
Reaction Cross Section
6
RLT and Relativity

• The longitudinal component of the relativistic
  electromagnetic nuclear current contains
  additional spin-orbit term.
• This additional term can interfere with the
  spin-flip magnetization term in the transverse
  current component.
• But, non-relativistically, there is no such
  additional term since L reflects charge only and
  can not interfere with the spin-flip part of T.
• Therefore, we can test relativistic models by
  separating RLT.

7
Run Summary
Neutron Direction Q2 (GeV/c)2 Pm (MeV/c) xB FSI MEC / IC Motivation
Parallel (pm q) 2.1 100, 200, 300, 400 and 500 lt 1 Minimum Maximum Emphasize MEC / IC
Anti-Parallel (pm - q) 2.1 100, 200, 300, 400 and 500 gt 1 Minimum Minimum Study Deuteron Short-range Structure
Perpendic-ular (pm ? q) 0.8 2.1 3.5 0, 100, 200, 300, 400 and 500 1 Variable Minimum Test Relativistic Models (RLT)
Neutron Angular Distribution 0.8 2.1 3.5 0, 100, 200, 300, 400 and 500 Variable Variable Variable Study FSI
8
Mean versus Most Probable Energy Loss (ELoss)
Emiss (MeV)
Emiss (MeV)
9
ARC versus Tiefenbach Beam Energy

• The dependence of Emiss on the beam energy for 2H
  is calculated for the shown runs from the same
  kinematics. The nominal ARC EBeam 2843.6 MeV.

Run ARC Emiss (MeV) Tief. EBeam (MeV) Tief. Emiss (MeV) dEmiss (MeV)(ARC - Tief.)
1242 3.5 2843.5 3.5 0.0
1243 3.6 2843.5 3.6 0.0
1252 4.0 2843.1 3.7 0.3
1254 3.9 2843.1 3.5 0.4

• This table shows that the variations in the Tief.
  beam energy are adequate to calculate the actual
  beam energy for each run.

10
Coincidence Time
Q3D f20l
11
Scintillator Calibration
Q3D f20l Q3D f20r
12
Beam Current
13
Beam Position
14
Kinematics Calibration

• Use different hydrogen elastic kinematics at the
  same EBeam.
• Minimize the ?W, ?Em, ?pmx, ?pmy and ?pmz offsets
  (?yj, j1,,5) between the data and the
  simulation (W ? Mp, Em ? 0, pm ? 0).
• Fit for the relative momentum deviations, ?e
  ?e'/e' and ?p ?p/p, the in-plane angular
  offsets, ?qe and ?qp and the out-of-plane angular
  offsets, ?fe and ?fp (?xi, i1,,6) to minimize
  ?yj.

15
Original Variable Offsets

• A new code was written to fit for the kinematics
  offsets by minimizing the variable offsets in
  this table.

Run EBeam (MeV) k (MeV) p (MeV) ?e (mr) ?p (mr) dW (MeV) dEm (MeV) dpmx (MeV) dpmy (MeV) dpmz (MeV)
2594 5008.4 2918.5 2877.3 30.474 -30.483 9.966 2.239 3.221 0.847 0.863
2596 5008.4 3159.3 2617.4 26.981 -33.301 10.858 2.347 4.008 0.841 1.001
2599 5008.4 3425.2 2338.9 23.979 -36.579 10.771 2.563 4.214 -0.394 1.358
2600 5008.4 3695.4 2044.6 20.980 -40.398 8.799 1.835 3.944 -0.978 0.696
2632 5008.4 3140.3 2648.0 27.265 -32.917 9.836 2.323 3.599 0.606 1.290
2672 5008.5 3140.3 2648.0 27.265 -32.917 9.902 2.059 3.830 0.347 0.964
2792 5008.5 3140.2 2648.0 27.264 -32.927 11.061 2.525 4.096 0.554 1.300
16
Minimized Variable Offsets

• The minimized variable offsets after the
  kinematics calibration are shown in this table.

Run dW (MeV) dEm (MeV) dpmx (MeV) dpmy (MeV) dpmz (MeV)
2594 -0.526 -0.168 -0.359 -0.220 -0.239
2596 0.652 0.027 0.216 0.401 -0.064
2599 0.818 0.335 0.188 -0.152 0.353
2600 -0.732 -0.292 -0.326 -0.028 -0.265
2632 -0.402 -0.011 -0.182 0.102 0.218
2672 -0.336 -0.275 0.049 -0.157 -0.109
2792 0.824 0.192 0.315 0.050 0.228
17
Kinematics Offsets
?e (x10-3) ?p (x10-3) ?qe (mr) ?qp (mr) ?fe (mr) ?fp (mr)
Offsets -0.287 -0.574 -1.146 -0.448 1.054 -1.440
Uncert. 0.173 0. 232 0.117 0.132 0.230 0.291
18
Missing Energy (Emiss)
Data (MeV/c2) Data (MeV/c2) Simulation (MeV/c2) Simulation (MeV/c2)
Kinematics Left Right Left Right
Q3D f00 2.3531 2.3531 2.51 2.51
Q3D f10 2.10 2.71 2.55 2.55
Q3D f20 2.42 3.10 2.64 2.45
Q3D f30 2.51 3.15 2.79 2.45
Q3D f40 2.25 3.05 2.80 2.57
Q3D f50 - 2.95 - 2.62
19
Relative Momentum Deviation (dp)
Q3D f20l
Q3D f20r
Simulation Data
20
PID (Cerenkov Detector)
99 Efficiency
ECSUM gt 150
21
PID (Pion Rejector)
99 Efficiency
PRSUM Cut
22
Theoretical Calculations

• We have now Lagets PWIA calculations fully
  integrated with the recent official MCEEP
  version.
• We hope that the full Lagets calculations will
  be available soon to us (This will include all
  the different mechanisms such as FSI, MEC and IC.
• We also expect to use Sargsians calculations
  once they are made available to us.

23
Summary

• The experiment ran in 2002 for 2 months and
  collected about 2 TB of data for more than 120
  different kinematics.
• All the optimizations and calibrations of the two
  spectrometers have been completed or are
  finishing up.
• Extensive software improvements and additions
  have been made in ESPACE and MCEEP.
• Many new standalone codes were written to display
  and optimize the different aspects of the data.
• Several passes through the data were done to
  correct for the beam position and to extract the
  stable current time periods.
• Lagets PWIA grid interpolation was implemented
  in MCEEP.
• The highest Q2 final results are expected by the
  end of 2006.