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Title: Influence of relativistic dynamics and density-dependent corrections on the induced polarization and analyzing power for exclusive 1s{sub 1/2} proton knockout in {sup 12}C

Abstract

Induced polarization and analyzing power data for exclusive proton-induced proton knockout from the 1s{sub 1/2}-state in {sup 12}C - at incident energies of 392 MeV and 1 GeV and for kinematics corresponding to zero recoil momentum - are studied within the framework of both relativistic and nonrelativistic distorted wave models based on the impulse approximation. We also study to which extent relativistic dynamical effects can be simulated in the nonrelativistic Schroedinger-equation-based distorted wave model via the introduction of effective nucleon mass corrections (within the context of the Walecka model of quantum hadrodynamics) to the nucleon-nucleon (NN) scattering matrix. A quantitative description of the data is achieved by invoking density-dependent corrections to the NN amplitudes within the framework of our relativistic distorted wave model.

Authors:
 [1];  [2];  [3]
  1. Department of Physics, University of Stellenbosch, Private Bag X1, Matieland 7602 (South Africa)
  2. (Japan)
  3. Department of Physics, Kyushu University, Fukuoka 812-8581 (Japan)
Publication Date:
OSTI Identifier:
20864213
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 74; Journal Issue: 6; Other Information: DOI: 10.1103/PhysRevC.74.064608; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; AMPLITUDES; CARBON 12; CARBON 12 TARGET; CORRECTIONS; DENSITY; DISTORTED WAVE THEORY; GEV RANGE; IMPULSE APPROXIMATION; KNOCK-OUT REACTIONS; MEV RANGE; NUCLEON-NUCLEON INTERACTIONS; POLARIZATION; POLARIZATION-ASYMMETRY RATIO; PROTON REACTIONS; PROTONS; RECOILS; RELATIVISTIC RANGE; SCATTERING; SCHROEDINGER EQUATION; WALECKA MODEL

Citation Formats

Hillhouse, G. C., Department of Physics, Kyushu University, Fukuoka 812-8581, and Noro, T. Influence of relativistic dynamics and density-dependent corrections on the induced polarization and analyzing power for exclusive 1s{sub 1/2} proton knockout in {sup 12}C. United States: N. p., 2006. Web. doi:10.1103/PHYSREVC.74.064608.
Hillhouse, G. C., Department of Physics, Kyushu University, Fukuoka 812-8581, & Noro, T. Influence of relativistic dynamics and density-dependent corrections on the induced polarization and analyzing power for exclusive 1s{sub 1/2} proton knockout in {sup 12}C. United States. doi:10.1103/PHYSREVC.74.064608.
Hillhouse, G. C., Department of Physics, Kyushu University, Fukuoka 812-8581, and Noro, T. Fri . "Influence of relativistic dynamics and density-dependent corrections on the induced polarization and analyzing power for exclusive 1s{sub 1/2} proton knockout in {sup 12}C". United States. doi:10.1103/PHYSREVC.74.064608.
@article{osti_20864213,
title = {Influence of relativistic dynamics and density-dependent corrections on the induced polarization and analyzing power for exclusive 1s{sub 1/2} proton knockout in {sup 12}C},
author = {Hillhouse, G. C. and Department of Physics, Kyushu University, Fukuoka 812-8581 and Noro, T.},
abstractNote = {Induced polarization and analyzing power data for exclusive proton-induced proton knockout from the 1s{sub 1/2}-state in {sup 12}C - at incident energies of 392 MeV and 1 GeV and for kinematics corresponding to zero recoil momentum - are studied within the framework of both relativistic and nonrelativistic distorted wave models based on the impulse approximation. We also study to which extent relativistic dynamical effects can be simulated in the nonrelativistic Schroedinger-equation-based distorted wave model via the introduction of effective nucleon mass corrections (within the context of the Walecka model of quantum hadrodynamics) to the nucleon-nucleon (NN) scattering matrix. A quantitative description of the data is achieved by invoking density-dependent corrections to the NN amplitudes within the framework of our relativistic distorted wave model.},
doi = {10.1103/PHYSREVC.74.064608},
journal = {Physical Review. C, Nuclear Physics},
number = 6,
volume = 74,
place = {United States},
year = {Fri Dec 15 00:00:00 EST 2006},
month = {Fri Dec 15 00:00:00 EST 2006}
}
  • Analyzing power data are reported for exclusive proton-induced proton knockout from the 1s{sub 1/2} states of 10 target nuclei ranging from {sup 2}H to {sup 19}F for an incident energy of 392 MeV. Compared to free proton-proton scattering, the data are significantly suppressed, the amount of suppression increasing monotonically as a function of increasing separation energies for the knocked-out protons. It is also possible to consider that this suppression increases monotonically as a function of the increasing effective mean density for most of the target nuclei, but data for {sup 3}He and {sup 4}He targets clearly deviate from such systematicmore » change. The data are compared to model predictions based on the nonrelativistic and relativistic distorted-wave impulse approximation. Both relativistic plane wave model and a nonrelativistic distorted-wave model incorporating a relativistic correction associated with an effective nucleon mass predict a significant suppression of the analyzing power, but the magnitude of the suppression is not sufficient to explain the experimental data. However, a relativistic distorted wave model predicts values that are closer to the data, but the result is inconclusive in this work since recoil corrections are neglected.« less
  • The influence of the collision energy (E{sub T}) on the O({sup 1}D) + RH {r{underscore}arrow} OH(X{sup 2}II) + R (RH = CH{sub 4}, C{sub 2}H{sub 6}, and C{sub 3}H{sub 8}) reaction dynamics has been studied, using the N{sub 2}O photodissociation at 193 nm as O({sup 1}D) precursor ({l{underscore}angle}E{sub T}{r{underscore}angle} = 0.403 eV) and probing the OH {upsilon}{double{underscore}prime} = 0 and 1 levels by LIF. A triatomic QCT study of the reaction with CH{sub 4} on a fully ab initio based analytical PES has also been performed, and a quite good agreement with the experimental OH rovibrational distributions has been obtained.more » The authors experimental results are similar to those obtained when the O{sub 3} photodissociation is used to produce O({sup 1}D) ({l{underscore}angle}E{sub T}{r{underscore}angle} = 0.212 eV), as expected on the basis of the available energy in products and also from the QCT calculations. The P({upsilon}{double{underscore}prime} = 0)/P({upsilon}{double{underscore}prime} = 1) populations ratio values reported for C{sub 2}H{sub 6} and C{sub 3}H{sub 8} in a very recent work (Wada and Obi, J.Phys.Chem.A 1998, 102, 3481), where the N{sub 2}O was also used to generate O({sup 1}D), are probably largely underestimated. The rotational distributions obtained are similar to those obtained in other experiments, and a quite good agreement has been obtained for the spin-orbit and {Lambda}-doublet populations. The reaction takes place near exclusively through the insertion of the O({sup 1}D) atom into a C-H bond below 0.6 eV, and the mechanism may be direct or nondirect (mainly through short-lived (CH{sub 3})OH collision complexes) with about the same probability. The OH vibrational distribution arising from the direct mechanism is inverted, while the nondirect one leads to a noninverted distribution. A higher E{sub T}, the abstraction mechanism also contributes appreciably to reactivity.« less
  • High precision measurements of the vapor pressure differences between some deuterated benzenes B-d/sub x/ (x=1, para-2, and 6) and protio benzene B-d/sub 0/; between para- and ortho-, and para- and meta-dideuterobenzene; and between perdeuterocyclohexane C-d/sub 12/ and protiocyclohexane C-d/sub 0/ were made from near the freezing point to the normal boiling point. The data are best represented as the logarithmic ratios ln R (d/sub 6/) =ln (P/sub d/0/P/sub d/6) =1226.5/T/sup 2/-12.178/T, ln R (para/ortho) =ln (P/sub parahyphend/2/P/sub orthohyphend/2) =2.6/T/sup 2/, and ln R (para/meta) =ln (P/sub parahyphend/2/P/sub metahyphend/2) =-2.0/T/sup 2/, together with the deviations from the law of the meanmore » ..delta.. (d1) =6-(ln R (d/sub 6/)/lnR (d/sub 1/))=0.177-3.6 x 10/sup -4/t and ..delta.. (d/sub 2hyphenpara/=3-(ln R (d/sub 6/)/ln R (d/sub 2hyphenpara/))=0.028 +1.0 x 10/sup -4/t. The isotope effects are inverse and display significant deviations from the law of the mean. The cyclohexane results are given by ln R (C-d/sub 12/) =-2188.4/T/sup 2/-18.587/T. New measurements of the vapor pressures of benzene--cyclohexane solutions are also reported between 5 and 80 /sup 0/C. The data are in good agreement with the best earlier work. Excess free energies of the equimolar solutions B-h/sub 6//B-d/sub 6/ and C-h/sub 12//C-d/sub 12/ have been measured between 20 and 80 /sup 0/C. Suitable fits to the data yield the following results (30 /sup 0/C); G/sup ex/(B-h/B-d), G/sup ex/(C-h/C-d); H/sup ex/(B-h/B-d),« less
  • The (p,p{alpha}) reaction on {sup 12}C was investigated experimentally using polarized incident protons of 100 MeV. The scattered proton and {alpha} particle, from the knockout reaction, were detected in coincidence. Coincident data, which were obtained at ten quasifree angle pairs for proton angles ranging from 25 deg. to 110 deg., were analyzed in terms of the distorted-wave impulse approximation (DWIA). Calculated energy-sharing cross section and analyzing power distributions reproduce the data reasonably well, indicating that a quasifree knockout mechanism dominates the reaction. Since measurements of analyzing powers were made, spin-orbit distortions were included in the DWIA calculations. The effects ofmore » this were found to be very small near zero recoil momentum and did not destroy the validity of the factorization approximation where the two-body p-{alpha} cross section enters as a multiplicative factor in the three-body (p,p{alpha}) cross section expression. Spectroscopic factors derived from the data are consistent with theoretical predictions. Analyzing power data also follow the trend of free p-{sup 4}He scattering data, and comparisons with DWIA predictions are in reasonable agreement. Because the two-body interaction response between the projectile and the {alpha} cluster was found to resemble the scattering of protons from a free {alpha} particle to a remarkable degree, the present results would strongly imply the existence of preformed {alpha} clusters in {sup 12}C.« less