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Dynamics of the quasielastic O-16(e,ep) reaction at Q2 = 0.8 (GeV/c)2

Fissum, Kevin LU (2004) In Physical Review C: covering nuclear physics 70(3).
Abstract
The physics program in Hall A at Jefferson Lab commenced in the summer of 1997 with a detailed investigation of the 16O(e,ep) reaction in quasielastic, constant (q,) kinematics at Q20.8 (GeV/c)2, q1 GeV/c, and 445 MeV. Use of a self-calibrating, self-normalizing, thin-film waterfall target enabled a systematically rigorous measurement. Five-fold differential cross-section data for the removal of protons from the 1p-shell have been obtained for 0<pmiss<350 MeV/c. Six-fold differential cross-section data for 0<Emiss<120 MeV were obtained for 0<pmiss<340 MeV/c. These results have been used to extract the ALT asymmetry and the RL, RT, RLT, and RL+TT effective response functions over a large range of Emiss and pmiss. Detailed... (More)
The physics program in Hall A at Jefferson Lab commenced in the summer of 1997 with a detailed investigation of the 16O(e,ep) reaction in quasielastic, constant (q,) kinematics at Q20.8 (GeV/c)2, q1 GeV/c, and 445 MeV. Use of a self-calibrating, self-normalizing, thin-film waterfall target enabled a systematically rigorous measurement. Five-fold differential cross-section data for the removal of protons from the 1p-shell have been obtained for 0<pmiss<350 MeV/c. Six-fold differential cross-section data for 0<Emiss<120 MeV were obtained for 0<pmiss<340 MeV/c. These results have been used to extract the ALT asymmetry and the RL, RT, RLT, and RL+TT effective response functions over a large range of Emiss and pmiss. Detailed comparisons of the 1p-shell data with Relativistic Distorted-Wave Impulse Approximation (RDWIA), Relativistic Optical-Model Eikonal Approximation (ROMEA), and Relativistic Multiple-Scattering Glauber Approximation (RMSGA) calculations indicate that two-body currents stemming from meson-exchange currents (MEC) and isobar currents (IC) are not needed to explain the data at this Q2. Further, dynamical relativistic effects are strongly indicated by the observed structure in ALT at pmiss300 MeV/c. For 25<Emiss<50 MeV and pmiss50 MeV/c, proton knockout from the 1s1/2-state dominates, and ROMEA calculations do an excellent job of explaining the data. However, as pmiss increases, the single-particle behavior of the reaction is increasingly hidden by more complicated processes, and for 280<pmiss<340 MeV/c, ROMEA calculations together with two-body currents stemming from MEC and IC account for the shape and transverse nature of the data, but only about half the magnitude of the measured cross section. For 50<Emiss<120 MeV and 145<pmiss<340 MeV/c, (e,epN) calculations which include the contributions of central and tensor correlations (two-nucleon correlations) together with MEC and IC (two-nucleon currents) account for only about half of the measured cross section. The kinematic consistency of the 1p-shell normalization factors extracted from these data with respect to all available 16O(e,ep) data is also examined in detail. Finally, the Q2-dependence of the normalization factors is discussed. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review C: covering nuclear physics
volume
70
issue
3
publisher
American Physical Society
external identifiers
  • WOS:000224325900037
  • Scopus:20844436288
DOI
10.1103/PhysRevC.70.034606
language
English
LU publication?
yes
id
78b47dc8-4f3d-413d-800b-fb065553c404 (old id 713548)
date added to LUP
2007-12-11 13:20:24
date last changed
2016-10-13 04:38:09
@misc{78b47dc8-4f3d-413d-800b-fb065553c404,
  abstract     = {The physics program in Hall A at Jefferson Lab commenced in the summer of 1997 with a detailed investigation of the 16O(e,ep) reaction in quasielastic, constant (q,) kinematics at Q20.8 (GeV/c)2, q1 GeV/c, and 445 MeV. Use of a self-calibrating, self-normalizing, thin-film waterfall target enabled a systematically rigorous measurement. Five-fold differential cross-section data for the removal of protons from the 1p-shell have been obtained for 0&lt;pmiss&lt;350 MeV/c. Six-fold differential cross-section data for 0&lt;Emiss&lt;120 MeV were obtained for 0&lt;pmiss&lt;340 MeV/c. These results have been used to extract the ALT asymmetry and the RL, RT, RLT, and RL+TT effective response functions over a large range of Emiss and pmiss. Detailed comparisons of the 1p-shell data with Relativistic Distorted-Wave Impulse Approximation (RDWIA), Relativistic Optical-Model Eikonal Approximation (ROMEA), and Relativistic Multiple-Scattering Glauber Approximation (RMSGA) calculations indicate that two-body currents stemming from meson-exchange currents (MEC) and isobar currents (IC) are not needed to explain the data at this Q2. Further, dynamical relativistic effects are strongly indicated by the observed structure in ALT at pmiss300 MeV/c. For 25&lt;Emiss&lt;50 MeV and pmiss50 MeV/c, proton knockout from the 1s1/2-state dominates, and ROMEA calculations do an excellent job of explaining the data. However, as pmiss increases, the single-particle behavior of the reaction is increasingly hidden by more complicated processes, and for 280&lt;pmiss&lt;340 MeV/c, ROMEA calculations together with two-body currents stemming from MEC and IC account for the shape and transverse nature of the data, but only about half the magnitude of the measured cross section. For 50&lt;Emiss&lt;120 MeV and 145&lt;pmiss&lt;340 MeV/c, (e,epN) calculations which include the contributions of central and tensor correlations (two-nucleon correlations) together with MEC and IC (two-nucleon currents) account for only about half of the measured cross section. The kinematic consistency of the 1p-shell normalization factors extracted from these data with respect to all available 16O(e,ep) data is also examined in detail. Finally, the Q2-dependence of the normalization factors is discussed.},
  author       = {Fissum, Kevin},
  language     = {eng},
  number       = {3},
  publisher    = {ARRAY(0x9f34f78)},
  series       = {	Physical Review C: covering nuclear physics},
  title        = {Dynamics of the quasielastic O-16(e,ep) reaction at Q<sup>2</sup> = 0.8 (GeV/c)<sup>2</sup>},
  url          = {http://dx.doi.org/10.1103/PhysRevC.70.034606},
  volume       = {70},
  year         = {2004},
}