The contribution of 2N photon absorption in 12C(γ,2N) reactions for Eγ = 150–400 MeV

doi:10.1016/0370-2693(96)00508-4

Physics Letters B

Volume 380, Issues 3–4, 11 July 1996, Pages 247-252

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Abstract

The ¹²C(γ,pn) and ¹²C(γ,pp) reactions have been studied using tagged photons of energy E_γ = 150–400 MeV. Recoil momentum distributions are compared to the results of Monte Carlo calculations based on a two-nucleon photon absorption model and two different phase space models. The ¹²C(γ,pn) data at low missing energy are consistent with absorption on 1p² and 1s1p nucleon pairs.

References (18)

K. Gottfried
Nucl. Phys.
(1958)
M. Vanderhaeghen
Nucl. Phys. A
(1994)
I.J.D. MacGregor
Nucl. Phys. A
(1991)
S.M. Doran
Nucl. Phys. A
(1993)
S.J. Hall
Nucl. Instr. Meth. A
(1996)
I. Anthony
Nucl. Instr. Meth. A
(1991)
H. HerminghausTh. Walcher
Prog. Part. Nucl. Phys.
(1990)
P. Grabmayr
R.A. Cecil et al.
Nucl. Instr. Meth. A
(1979)
R.C. Carrasco et al.
Nucl. Phys. A
(1992)
R.C. Carrasco et al.
Nucl. Phys. A
(1994)
J. Ryckebusch
Nucl. Phys. A
(1994)

There are more references available in the full text version of this article.

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The photo-emission of two protons from the ¹²C, ¹⁶O and ⁴⁰Ca nuclei is investigated. Aim of the work is the study of the possibilities offered by this probe to obtain information about the characteristics of the short-range correlations. We have also evaluated the effects of the two-body Δ-currents which, in this processes, compete with those produced by the short-range correlations. Our results show that $(γ, pp)$ processes could be more useful than $(e, e^{'} pp)$ for the study of the short-range correlations.
12C(γ→,pn) photon asymmetry for Eγ = 180-340 MeV
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The photon asymmetry (Σ) of the $^{12}$ C( $γ →$ ,pn) reaction has been measured using linearly polarised tagged photons at the Mainz microtron MAMI for E_γ=180–340 MeV. The data have been analysed in separate missing energy (E_m) regions corresponding to the ejection of nucleons from (1p)² and (1p)(1s) shells. The measured Σ values for both E_m regions are smaller in magnitude than corresponding $^{2}$ H data, but the (1p)² results have a similar E_γ dependence. Calculations of direct two-nucleon emission overestimate the magnitude of Σ at all photon energies.
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¹: Present address: Psion plc, London, U.K.

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Physics Letters B

Abstract

References (18)

Nucl. Phys.

Nucl. Phys. A

Nucl. Phys. A

Nucl. Phys. A

Nucl. Instr. Meth. A

Nucl. Instr. Meth. A

Prog. Part. Nucl. Phys.

Nucl. Instr. Meth. A

Nucl. Phys. A

Nucl. Phys. A

Nucl. Phys. A

Cited by (21)

Energy levels of light nuclei A = 12

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<sup>12</sup>C(γ<sup>→</sup>,pn) photon asymmetry for Eγ = 180-340 MeV

Photon-induced two-nucleon knockout reactions to discrete final states

Investigation of short-range nucleon-nucleon correlations using the reaction <sup>12</sup>C( e,e′ pp) in close to 4π geometry