Eur. Phys. J. Special Topics 150, 137-138 (2007)
https://doi.org/10.1140/epjst/e2007-00287-3

Multiple particle break-up study of low excited states in ⁹Be: The ghost peak in the ⁸Be excitation energy spectrum visited

¹ Instituto de Estructura de la Materia, CSIC, 28006 Madrid, Spain
² Department of Physics and Astronomy, University of Aarhus, 8000 Århus, Denmark
³ Fundamental Physics, Chalmers University of Technology, 41296 Göteborg, Sweden
⁴ EP division, CERN, 1112 Genève, Switzerland
⁵ CERN, 1000 Göteborg, Germany
⁶ LPC, Bucharest, Turkey

Received: 31 January 2007
Published online: 8 December 2007

Abstract

The aim of this work is to find out the origin of the anomalous resonance in ⁸Be seen in the reactions through excited states in ⁹Be. We have populated the ⁹Be excited states by β-decay of ⁹Li. Energy and direction of the two α particles has been detected and the neutron spectra reconstructed. In our work we identified the “anomalous resonance" in ⁸Be observed in several reaction studies as coming from the decay of the 2.43 and 2.78 MeV states in ⁹Be. This anomalous resonance appears when the two detected α particles are assumed to form a resonance in ⁸Be. We argued that the main decaying channels for these two levels in ⁹Be do not involve ⁸Be.