Relativistic DWBA calculations for medium energy photonuclear reactions

Lotz, G.M.; Sherif, H. S.

doi:10.1016/0370-2693(88)90346-2

Cited by 18 publications

(12 citation statements)

References 21 publications

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“…where the wave functions of the continuum and bound nucleons, denoted Ψ µ and Ψ J B ,M B respectively, are solutions of the Dirac equation containing appropriate potentials [4]. The 4 × 4 matrix Γ α , operating on the nucleon spinors is given in Eq.…”

Section: The Relativistic Calculationsmentioning

confidence: 99%

“…The purpose of the present paper is to report on similar comparative calculations carried out within a relativistic mean field approach. We have recently carried out relativistic distorted wave calculations for the DKO contributions to (γ, p) reactions [4]. There have also been several similar calculations for the (e, e ′ p) reaction [5,6,7,8].…”

Section: Introductionmentioning

confidence: 99%

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Relativistic calculations for photonuclear reactions (III): A consistent relativistic analysis of the (e, e′p) and (γ, p) reactions

Johansson

Sherif

Lotz³

1996

Nuclear Physics A

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Single nucleon knockout reactions must be described in a consistent framework in order to extract information about nuclear structure and reaction mechanisms. Consistent relativistic models for the direct knockout contribution to the (e, e ′ p) and (γ, p) reactions have been developed and used previously to examine existing momentum distribution and cross section data for the two reactions 1 . We present results of calculations of spin observables obtained from these models of (e, e ′ p) and (γ, p) reactions. For the (e, e ′ p) reaction we consider the importance of the choice of kinematics and show that perpendicular kinematics result in distributions with relatively large cross sections and comparatively large polarizations. In the (γ, p) reactions the photon asymmetry and proton polarization are not very sensitive to changes in model ingredients when the incident photon energy is less than 100 M eV . For higher energies these observables show increasing sensitivity to modifications of both the bound and continuum wave functions.

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Section: The Relativistic Calculationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Relativistic calculations for photonuclear reactions (III): A consistent relativistic analysis of the (e, e′p) and (γ, p) reactions

Johansson

Sherif

Lotz³

1996

Nuclear Physics A

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“…where the wave functions of the continuum and bound nucleons, denoted Ψ µ and Ψ J B ,M B respectively, are solutions of the Dirac equation containing appropriate potentials [13]. The 4 × 4 matrix Γ β , operating on the nucleon spinors, and the four-vector which comes from the electron vertex, e β ν f ν i in Eq.…”

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confidence: 99%

Relativistic calculations of induced polarization in12C(e,e′p
Johansson
¹
,
Sherif
²

1999
Phys. Rev. C
11
3
19
0
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Relativistic calculations of the induced proton polarization in quasifree electron scattering on 12 C are presented. Good agreement with the experimental data of Woo et al. is obtained. The relativistic calculations yield a somewhat better description of the data than the nonrelativistic ones. Differences between the two approaches are more pronounced at larger missing momenta suggesting further experimental work in this region.

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“…This theoretical shortcoming has motivated many calculations that have separately investigated different mechanisms thought to be important, such as nucleon-nucleon correlations [1,2], relativistic equations of motion [3][4][5], meson exchange currents [6][7][8][9], and excitation of A(1232) resonances [10,11]. Despite such efforts, the available (7,p) data [12][13][14] below 400 MeV are described at best only semiquantitatively, while the computed (7, n) cross sections [15] are not even qualitatively described.…”

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confidence: 99%

Simultaneous microscopic description ofO16(γ,n) andO
Bright
¹
,
Cotanch
²

1993
Phys. Rev. Lett.
11
0
4
1
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The photonuclear reactions 16 0(7,n) 15 0 and 16 0(7,p) 15 N are simultaneously described within a coupled channels framework based on a continuum shell model formulation that includes all nonlocalities arising from antisymmetrization. This large-scale conventional many-body calculation provides a good description of the medium energy data. The inclusion of A(1232) degrees of freedom further, but slightly, improves the description of the available data. Complete quantitative agreement, however, is still lacking.PACS numbers: 25.20.Lj, 24.10.EqThe apparent inability to describe and understand fully photonuclear reactions below 400 MeV using conventional, nonrelativistic dynamics has attracted growing theoretical and experimental interest. This theoretical shortcoming has motivated many calculations that have separately investigated different mechanisms thought to be important, such as nucleon-nucleon correlations [1,2], relativistic equations of motion [3][4][5], meson exchange currents [6-9], and excitation of A(1232) resonances [10,11]. Despite such efforts, the available (7,p) data [12-14] below 400 MeV are described at best only semiquantitatively, while the computed (7, n) cross sections [15] are not even qualitatively described. The purpose of this Letter is to report a large-scale, supercomputer-based ab initio calculation that includes both nucleon correlations and A(1232) isobar excitations. Our objective is to provide a realistic microscopic framework within which to consistently assess the importance of the aforementioned effects. We find that A(1232) isobar effects are small except at very large momentum transfer, and that a comprehensive conventional manybody structure calculation is sufficient to obtain the correct magnitude and qualitative features for both (7,p) and (7, n) reactions over a wide range of energies and angles.The calculation is a generalization of the microscopic continuum shell model treatment originally developed by Buck and Hill [16]. The many-body Hamiltonian for 16 0 is diagonalized rigorously in a model space spanned by products of continuum single-particle states and the mass A = 15 bound states. We use a realistic two-body, finiterange nucleon-nucleon interaction with spin, isospin, and tensor components, and we rigorously include all nonlocalities arising from antisymmetrization. The central N-N interaction between nucleons i and j is V c [a 0 -f a

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Relativistic DWBA calculations for medium energy photonuclear reactions

Cited by 18 publications

References 21 publications

Relativistic calculations for photonuclear reactions (III): A consistent relativistic analysis of the (e, e′p) and (γ, p) reactions

Relativistic calculations for photonuclear reactions (III): A consistent relativistic analysis of the (e, e′p) and (γ, p) reactions

Relativistic calculations of induced polarization in12C(e,e′p
Johansson
¹
,
Sherif
²

1999
Phys. Rev. C
11
3
19
0
View full text Add to dashboard Cite

Simultaneous microscopic description ofO16(γ,n) andO
Bright
¹
,
Cotanch
²

1993
Phys. Rev. Lett.
11
0
4
1
View full text Add to dashboard Cite

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Relativistic DWBA calculations for medium energy photonuclear reactions

Cited by 18 publications

References 21 publications

Relativistic calculations for photonuclear reactions (III): A consistent relativistic analysis of the (e, e′p) and (γ, p) reactions

Relativistic calculations for photonuclear reactions (III): A consistent relativistic analysis of the (e, e′p) and (γ, p) reactions

Relativistic calculations of induced polarization in12C(e,e′pJohansson1, Sherif2 1999Phys. Rev. C113190View full textAdd to dashboardCite

Simultaneous microscopic description ofO16(γ,n) andOBright1, Cotanch2 1993Phys. Rev. Lett.11041View full textAdd to dashboardCite

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Relativistic calculations of induced polarization in12C(e,e′p
Johansson
¹
,
Sherif
²

1999
Phys. Rev. C
11
3
19
0
View full text Add to dashboard Cite

Simultaneous microscopic description ofO16(γ,n) andO
Bright
¹
,
Cotanch
²

1993
Phys. Rev. Lett.
11
0
4
1
View full text Add to dashboard Cite