Coherent dissociation of relativistic 12N nuclei

Abstract

The dissociation of relativistic 12 N nuclei having a momentum of 2 GeV/c per nucleon and undergoing the most peripheral interactions in a track emulsion is studied. The picture of charged topology of product ensembles of relativistic fragments and special features of their angular distributions are presented. DOI: 10.1134/S1063778813100074The track-emulsion method has still retained its exceptional position as a means for studying the structure of fragmentation of relativistic nuclei owing to the completeness of observation of fragment ensembles and owing to its record spatial resolution. The objective of employing a track emulsion in the Becquerel project [1] at the nuclotron of the Joint Institute for Nuclear Research (JINR, Dubna) is to study the clustering of nucleons for a wide variety of light nuclei, including radioactive ones. An analysis proves to be the most comprehensive for coherent-dissociation events, in which target fragments or mesons are not produced [2] and which, for the sake of brevity, are referred to as white stars. Since the perturbation is minimal in interactions of this type, a configuration overlap of the ground states of the nuclei being studied and the observed ensembles of fragments and nucleons manifests itself. On this basis, there arise possibilities for some kind of a tomography of the nuclear structure. The distribution of white stars with respect to the probability for the formation of various configurations shows a correlation with weights of respective cluster components of the nuclei being studied. The discovery of the contribution from unexplored and even unexpected components of deeply bound cluster states is possible on this path. This is so especially for proton-rich light nuclei. The picture of nucleon clustering in events of the coherent dissociation of the 12 N radioactive nucleus, which has yet to receive adequate study, on track-emulsion nuclei is the

Unstable nuclei in dissociation of light stable and radioactive nuclei in nuclear track emulsion

“…Contribution of the unstable nuclei 6 Be, 8 Be and 9 B into dissociation of relativistic nuclei 7,9 Be, 10 B and 10,11 C is under study on the basis of the nuclear track emulsion exposed to secondary beams of the JINR Nuclotron.…”

“…The feature of 7 Be dissociation is an approximate equality of probability of the main channels 2He and He + 2H of coherent dissociation (Table I). Their ratio is equal to 0.7 ± 0.1 [11]. Recently obtained statistics of 140 10 B "white" stars is presented in The unstable nuclei in dissociation of the 9 Be, 10 Earlier, basing on the Q αp energy distribution of the triples 2α + p from the "white" stars 10 C → 2α + 2p it is concluded that in the 10 C nucleus the core 9 B is manifested with a probability of 30 ± 4%, and the 8 Be g.s.…”

“…Application of NTE is especially justified in those pioneering experiments in which nuclear particle tracks can not be reconstructed with the help of electronic detectors. Thus, in the last decade in the framework of the BECQUEREL Project in JINR the NTE technique allowed one to investigate clustering of the nuclei 7 Li, 7,9 Be, 8,10 B, 9,10 C and 12,14 N in their relativistic dissociation [4][5][6][7][8][9][10][11][12][13].…”

Charge topology of the coherent dissociation of relativistic 11C and 12N nuclei

“…From the experimental point of view, the last channel is a three-body one and can involve the decays of both the ground state (0 + ) of the 8 Be nucleus and its 2 + excited state. Moreover, channels that, in charge topology, correspond to the dissociation of the 7 Be and 10 B core nuclei should appear. Thereby, one expects that the role of multi-particle channels in the coherent cluster dissociation of 11 C nuclei should be significant, so that the application of the nuclear-track-emulsion method is reasonable.…”

“…The decay of the 11 C nucleus leads to the formation of the stable isotope 11 B, which one can observe in cosmic rays. This scenario of nucleosynthesis is not commonly recognized-the isotopes 10,11 B are assumed to be products of the bombardment of carbon-star surfaces with high-energy protons. If observations reveal the dissociation of 11 C nuclei through the 7 Be + α and 3 He + 8 Be channels, this would confirm the existence of cluster modes in this nucleus that are genetically related to its synthesis.…”