Helicity dependence of the d NN reactions in the -resonance region

J. Ahrens; S. Altieri; J. R. M. Annand; H. -J. Arends; R. Beck; M. A. Blackston; C. Bradtke; A. Braghieri; N. d’Hose; H. Dutz; A. Fix; E. Heid; O. Jahn; F. Klein; R. Kondratiev; M. Lang; V. Lisin; M. Martinez-Fabregate; J. C. McGeorge; W. Meyer; A. Panzeri; P. Pedroni; T. Pinelli; D. Protopopescu; G. Reicherz; Ch. Rohlof; G. Rosner; T. Rostomyan; D. Ryckbosch; M. Schwamb; G. Tamas; A. Thomas; H. R. Weller

doi:10.1140/epja/i2010-10946-6

2022 Impact factor 2.7

Hadrons and Nuclei

Eur. Phys. J. A (2010) 44: 189-201
https://doi.org/10.1140/epja/i2010-10946-6

Regular Article - Experimental Physics

Helicity dependence of the d NN reactions in the -resonance region

The GDH and A2 Collaborations
J. Ahrens⁷, S. Altieri⁹^,10, J. R. M. Annand⁶, H. -J. Arends⁷, R. Beck⁷^,a, M. A. Blackston³, C. Bradtke², A. Braghieri⁹, N. d’Hose⁵, H. Dutz², A. Fix¹¹, E. Heid⁷, O. Jahn⁷, F. Klein², R. Kondratiev⁸, M. Lang⁷^,a, V. Lisin⁸, M. Martinez-Fabregate⁷, J. C. McGeorge⁶, W. Meyer¹, A. Panzeri⁹^,10, P. Pedroni⁹^*, T. Pinelli⁹^,10, D. Protopopescu⁶, G. Reicherz¹, Ch. Rohlof², G. Rosner⁶, T. Rostomyan⁴^,9, D. Ryckbosch⁴, M. Schwamb⁷, G. Tamas⁷, A. Thomas⁷ and H. R. Weller³

¹ Insitut für Experimentalphysik, Ruhr-Universität Bochum, D-44801, Bochum, Germany
² Physikalisches Institut, Universität Bonn, D-53115, Bonn, Germany
³ Department of Physics, Duke University, 27708, Durham, NC, USA
⁴ Subatomaire en Stralingsfysica, Universiteit Gent, B-9000, Gent, Belgium
⁵ CEA Saclay, DSM/DAPNIA/SPhN, F-91191, Gif-sur-Yvette Cedex, France
⁶ Department of Physics and Astronomy, University of Glasgow, G12 8QQ, Glasgow, UK
⁷ Institut für Kernphysik, Universität Mainz, D-55099, Mainz, Germany
⁸ INR, Academy of Science, Moscow, Russia
⁹ INFN, Sezione di Pavia, I-27100, Pavia, Italy
¹⁰ Dipartimento di Fisica Nucleare e Teorica, Università di Pavia, I-27100, Pavia, Italy
¹¹ Laboratory of Mathematical Physics, Tomsk Polytechnic University, 634050, Tomsk, Russia

^* e-mail: pedroni@pv.infn.it

Received: 26 October 2009
Revised: 26 February 2010
Accepted: 1 March 2010
Published online: 26 March 2010

Abstract

The helicity dependence of the differential cross-section for the d NN reactions has been measured for the first time in the -resonance region. The measurement was performed with the large-acceptance detector DAPHNE at the tagged photon beam facility of the MAMI accelerator in Mainz. The data show that the main reaction mechanisms for the NN channels are the quasi-free N processes on one bound nucleon with nuclear dynamics playing a minor role. On the contrary, for the np channel nuclear mechanisms involving the reabsorption of the photoproduced by the np pair have to be taken into account to reproduce the experimental data.