Role of 8Be → 2 α intermediate nuclei in the fragmentation of 16O relativistic nuclei in nuclear track emulsions

• Published in: Physics of atomic nuclei 2012-08, Vol.75 (8), p.984-988
• Main Authors: Lepekhin, F. G., Tkach, L. N.
• Format: Article
• Language: English
• Subjects: Elementary Particles and Fields; Particle and Nuclear Physics; Physics; Physics and Astronomy
• ISSN: 1063-7788; 1562-692X
• DOI: 10.1134/S1063778812040102

In searches along a track in the chamber irradiated at the Laboratory of High Energies at the Joint Institute for Nuclear Research (JINR, Dubna) with oxygen ions accelerated to a momentum of 4.5 GeV/ c per nucleon, 215 events containing two or more doubly charged fragments of the primary nucleus were found. Emission angles in the track-emulsion plane were measured in these events. Their distribution is consistent with that which alpha particles are expected to have in an oxygen nucleus prior to its interaction with a track-emulsion nucleus. Events of the 16 O → 2 8 Be → 4 α type were discovered for the first time. They are treated as events of the coherent electromagnetic dissociation of an oxygen nucleus. Among all events, about 14% of the 8 Be → 2 α decays proceed through the ground state of spin-parity 0 + ; an approximately the same fraction of such decays proceed through the first excited state of spin-parity 2 + .