Three-body correlations in electromagnetic dissociation of Borromean nuclei: The He-6 case

• Published in: Nuclear physics. A Vol. 759; no. 1-2; p. 23
• Main Authors: Chulkov, L. V., Simon, H., Thompson, I. J., Aumann, T., Borge, M. J. G., Elze, T. W., Emling, H., Geissel, H., Grigorenko, L. V., Hellstrom, M., Jonson, Björn, Kratz, J. W. V., Kulessa, R., Markenroth, K., Meister, Mikael, Munzenberg, G., Nickel, F., Nilsson, Thomas, Nyman, Göran Hugo, Pribora, V., Richter, A., Riisager, K., Scheidenberger, C., Schrieder, G., Tengblad, O., Zhukov, Mikhail
• Format: Journal Article
• Language: English
• Published: 05.09.2005
• Subjects: Coulomb excitation; EXCITATIONS; FRAGMENTATION; GENERAL-ORDER COLLISIONS; HALO NUCLEI; He-6; particle correlations; RESONANCE; TERTIARY; unstable nuclei
• ISSN: 0375-9474
• DOI: 10.1016/j.nuclphysa.2005.05.001

Dissociation of He-6 on a lead target has been studied at 240 MeV/u. The four-momenta of the two neutrons in coincidence with alpha-particles have been measured and used to reconstruct the three-body energy and angular correlations in the final state. For the first time, three-body correlations were included in the analysis of the He-6 dissociation data, and compared with calculations assuming a dipole mode for the electromagnetic dissociation. In addition, the experimental data have been analyzed using a series expansion of the final transition amplitude into hyperspherical functions, showing the importance of both nn and alpha n final-state interactions. It is shown that the dissociation process is governed by a transition of one neutron from the p-shell in the 6He ground state to the s-shell in the continuum further indicating that the role of the transition through an intermediate He-5(3/2(-)) state is more important than expected. (c) 2005 Elsevier B.V. All rights reserved.