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The European Physical Journal A
ISSN: 1434-6001 (printed version)
ISSN: 1434-601X (electronic version)
Abstract Volume 1 Issue 3 (1998) pp 241-244
short notes: The angular distribution of the 12C(<Gamma>,pn) reaction for E<Gamma>=120-150 MeV
T.T.-H. Yau (1), I.J.D. MacGregor (1), J. Ahrens (4), J.R.M. Annand (1), R. Beck (4), D. Branford (2), P. Grabmayr (3), S.J. Hall (1), P.D. Harty (1), T. Hehl (3), D.G. Ireland (1), J.D. Kellie (1), T. Lamparter (3), K. Livingston (1), M. Liang (2), J.A. MacKenzie (2), S. McAllister (1), J.C. McGeorge (1), R.O. Owens (1), M. Sauer (3), R. Schneider (3), D.P. Watts (1) (a)
(1) Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
(2) Department of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, UK
(3) Physikalisches Institut, Universität Tübingen, D-72076 Tübingen, Germany
(4) Institut für Kernphysik, Universität Mainz, D-55099 Mainz, Germany
Received: 3 September 1997 / Revised version: 17 December 1997
Abstract: The angular distribution of nucleons emitted in the 12C(<Gamma>,pn) reaction has been measured using tagged photons at the Mainz microtron MAMI. The variation of the reaction strength with the polar angles of the two emitted nucleons is reported for E<Gamma>=120-150 MeV. The proton angular distribution peaks at more backward angles than the 2H(<Gamma>,p) differential cross section indicating a departure from the simple quasi-deuteron model of 2N photo-emission. The distribution shape is in reasonable agreement with microscopic theoretical models which include both <pi>- and <rho>-exchange.
PACS: 21.30.Fe Forces in hadronic systems and effective interactions - 25.20.Lj Photoproduction reactions - 27.20.+n 6 \leq A \leq 19
(a) Present address: Chase Research, Basingstoke, UK
Communicated by Th. Walcher
Present address: Thomas Jefferson Lab, Newport News, USA
Online publication: March 13, 1998
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