EPJ

2011 Impact factor 1.562
EPJ ST - Special Topics
Special Topics
Eur. Phys. J. Special Topics 150, 23-26 (2007)
DOI: 10.1140/epjst/e2007-00256-x

Properties of low-lying 9He state

M.S. Golovkov1, L.V. Grigorenko1, A.S. Fomichev1, A.V. Gorshkov1, V.A. Gorshkov1, S.A. Krupko1, Yu.Ts. Oganessian1, A.M. Rodin1, S.I. Sidorchuk1, R.S. Slepnev1, S.V. Stepantsov1, G.M. Ter-Akopian1, R. Wolski1, 2, A.A. Korsheninnikov3, 4, E.Yu. Nikolskii3, 4, V.A. Kuzmin4, B.G. Novatskii4, D.N. Stepanov4, S. Fortier5, P. Roussel-Chomaz6 and W. Mittig

6

1 

Flerov Laboratory of Nuclear Reactions, JINR, 141980 Dubna, Russia
2  The Henryk Niewodniczanski Institute of Nuclear Physics, Kraków, Poland
3  RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
4  RRC "The Kurchatov Institute", Kurchatov sq. 1, 123182 Moscow, Russia
5  Institut de Physique Nucléaire, IN2P3-CNRS, 91406 Orsay, France
6  GANIL, BP. 5027, 14076 Caen Cedex 5, France


(Received: January 31, 2007 / Published online: 8 December 2007)

Abstract
The spectrum of 9He was studied by means of the 8He(d,p)9He reaction at a lab energy of 25 MeV/n and small center of mass (c.m.) angles. Energy and angular correlations were obtained for the 9He decay products by complete kinematical reconstruction. The data analysis was done in the assumption of a direct one-neutron transfer reaction mechanism. The 9He structure was analysed in the framework of a simple single-particle model. The lowest resonant state of 9He is found at about 2 MeV with a width of $\sim 2\,{\rm MeV}$ and is identified as 1/2-. The observed angular correlation pattern is uniquely explained by the interference of the 1/2- resonance with a virtual state 1/2+ (a limit on the scattering length is obtained as $a > -20\,{\rm fm}$), and with a 5/2+ resonance at energy $\geq 4.2\,{\rm MeV}$.

PACS
25.45.Hi - Transfer reactions.
24.50.+g - Direct reactions.
24.70.+s - Polarization phenomena in reactions.

© EDP Sciences, Springer-Verlag 2007