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Title: Dynamics of the quasielastic {sup 16}O(e,e{sup '}p) reaction at Q{sup 2}{approx_equal}0.8 (GeV/c){sup 2}

Abstract

The physics program in Hall A at Jefferson Lab commenced in the summer of 1997 with a detailed investigation of the {sup 16}O(e,e{sup '}p) reaction in quasielastic, constant (q,{omega}) kinematics at Q{sup 2}{approx_equal}0.8 (GeV/c){sup 2}, q{approx_equal}1 GeV/c, and {omega}{approx_equal}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<p{sub miss}<350 MeV/c. Six-fold differential cross-section data for 0<E{sub miss}<120 MeV were obtained for 0<p{sub miss}<340 MeV/c. These results have been used to extract the A{sub LT} asymmetry and the R{sub L}, R{sub T}, R{sub LT}, and R{sub L+TT} effective response functions over a large range of E{sub miss} and p{sub miss}. 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 Q{sup 2}. Further, dynamical relativistic effects are strongly indicated by the observed structure in A{sub LT} at p{sub miss}{approx_equal}300 MeV/c. For 25<E{sub miss}<50 MeV and p{sub miss}{approx_equal}50 MeV/c, proton knockout from the 1s{submore » 1/2}-state dominates, and ROMEA calculations do an excellent job of explaining the data. However, as p{sub miss} increases, the single-particle behavior of the reaction is increasingly hidden by more complicated processes, and for 280<p{sub miss}<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<E{sub miss}<120 MeV and 145<p{sub miss}<340 MeV/c (e,e{sup '}pN) 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 {sup 16}O(e,e{sup '}p) data is also examined in detail. Finally, the Q{sup 2}-dependence of the normalization factors is discussed.« less

Authors:
 [1]; ; ; ; ; ; ; ; ; ; ;  [2]; ; ; ; ; ;  [3];  [4];  [5]
  1. Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
  2. Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States)
  3. Kent State University, Kent, Ohio 44242 (United States)
  4. California State University Los Angeles, Los Angeles, California 90032 (United States)
  5. Temple University, Philadelphia, Pennsylvania 19122 (United States); and others
Publication Date:
OSTI Identifier:
20695527
Resource Type:
Journal Article
Journal Name:
Physical Review. C, Nuclear Physics
Additional Journal Information:
Journal Volume: 70; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevC.70.034606; (c) 2004 American Physical Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0556-2813
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ASYMMETRY; BOSON-EXCHANGE MODELS; CEBAF ACCELERATOR; COMPARATIVE EVALUATIONS; CORRELATIONS; DIFFERENTIAL CROSS SECTIONS; DISTORTED WAVE THEORY; EIKONAL APPROXIMATION; ELECTRON REACTIONS; ELECTRONS; GEV RANGE; IMPULSE APPROXIMATION; KNOCK-OUT REACTIONS; MEV RANGE; MULTIPLE SCATTERING; OPTICAL MODELS; OXYGEN 16; OXYGEN 16 TARGET; PROTONS; RELATIVISTIC RANGE; RESPONSE FUNCTIONS; THIN FILMS; TWO-BODY PROBLEM

Citation Formats

Fissum, K G, University of Lund, Box 118, SE-221 00 Lund, Liang, M, Cardman, L S, Chen, J -P, Jager, C.W. de, Domingo, J, Gomez, J, LeRose, J J, Michaels, R, Nanda, S, Saha, A, Wojtsekhowski, B, Anderson, B D, Khayat, M, Manley, D M, Petratos, G G, Prout, D L, Watson, J W, Aniol, K A, and Auerbach, L. Dynamics of the quasielastic {sup 16}O(e,e{sup '}p) reaction at Q{sup 2}{approx_equal}0.8 (GeV/c){sup 2}. United States: N. p., 2004. Web. doi:10.1103/PhysRevC.70.034606.
Fissum, K G, University of Lund, Box 118, SE-221 00 Lund, Liang, M, Cardman, L S, Chen, J -P, Jager, C.W. de, Domingo, J, Gomez, J, LeRose, J J, Michaels, R, Nanda, S, Saha, A, Wojtsekhowski, B, Anderson, B D, Khayat, M, Manley, D M, Petratos, G G, Prout, D L, Watson, J W, Aniol, K A, & Auerbach, L. Dynamics of the quasielastic {sup 16}O(e,e{sup '}p) reaction at Q{sup 2}{approx_equal}0.8 (GeV/c){sup 2}. United States. doi:10.1103/PhysRevC.70.034606.
Fissum, K G, University of Lund, Box 118, SE-221 00 Lund, Liang, M, Cardman, L S, Chen, J -P, Jager, C.W. de, Domingo, J, Gomez, J, LeRose, J J, Michaels, R, Nanda, S, Saha, A, Wojtsekhowski, B, Anderson, B D, Khayat, M, Manley, D M, Petratos, G G, Prout, D L, Watson, J W, Aniol, K A, and Auerbach, L. Wed . "Dynamics of the quasielastic {sup 16}O(e,e{sup '}p) reaction at Q{sup 2}{approx_equal}0.8 (GeV/c){sup 2}". United States. doi:10.1103/PhysRevC.70.034606.
@article{osti_20695527,
title = {Dynamics of the quasielastic {sup 16}O(e,e{sup '}p) reaction at Q{sup 2}{approx_equal}0.8 (GeV/c){sup 2}},
author = {Fissum, K G and University of Lund, Box 118, SE-221 00 Lund and Liang, M and Cardman, L S and Chen, J -P and Jager, C.W. de and Domingo, J and Gomez, J and LeRose, J J and Michaels, R and Nanda, S and Saha, A and Wojtsekhowski, B and Anderson, B D and Khayat, M and Manley, D M and Petratos, G G and Prout, D L and Watson, J W and Aniol, K A and Auerbach, L},
abstractNote = {The physics program in Hall A at Jefferson Lab commenced in the summer of 1997 with a detailed investigation of the {sup 16}O(e,e{sup '}p) reaction in quasielastic, constant (q,{omega}) kinematics at Q{sup 2}{approx_equal}0.8 (GeV/c){sup 2}, q{approx_equal}1 GeV/c, and {omega}{approx_equal}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<p{sub miss}<350 MeV/c. Six-fold differential cross-section data for 0<E{sub miss}<120 MeV were obtained for 0<p{sub miss}<340 MeV/c. These results have been used to extract the A{sub LT} asymmetry and the R{sub L}, R{sub T}, R{sub LT}, and R{sub L+TT} effective response functions over a large range of E{sub miss} and p{sub miss}. 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 Q{sup 2}. Further, dynamical relativistic effects are strongly indicated by the observed structure in A{sub LT} at p{sub miss}{approx_equal}300 MeV/c. For 25<E{sub miss}<50 MeV and p{sub miss}{approx_equal}50 MeV/c, proton knockout from the 1s{sub 1/2}-state dominates, and ROMEA calculations do an excellent job of explaining the data. However, as p{sub miss} increases, the single-particle behavior of the reaction is increasingly hidden by more complicated processes, and for 280<p{sub miss}<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<E{sub miss}<120 MeV and 145<p{sub miss}<340 MeV/c (e,e{sup '}pN) 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 {sup 16}O(e,e{sup '}p) data is also examined in detail. Finally, the Q{sup 2}-dependence of the normalization factors is discussed.},
doi = {10.1103/PhysRevC.70.034606},
journal = {Physical Review. C, Nuclear Physics},
issn = {0556-2813},
number = 3,
volume = 70,
place = {United States},
year = {2004},
month = {9}
}