Nuclear track emulsion is exposed to 1.2 A $^9$C GeV nuclei. Pairs of 2$^3$He nuclei having unusually narrow opening angles are observed in channel $^9$C $rightarrow$ 3$^3$He pointing to the possible 2$^3$He resonance near the production threshold.
The dissociation features in nuclear track emulsion of $^9$Be, $^{9,10}$C, and $^{12}$N nuclei of 1.2 A GeV energy are presented. The data presented for the nucleus $^9$Be can be considered as evidence that there is a core in its structure in the for
m of 0$^+$ and 2$^+$ states of the $^8$Be nucleus having roughly equal weights. Events of coherent dissociation $^9$C$rightarrow 3^3$He associated with the rearrangement of the nucleons outside the $alpha$-clustering are identified. A pattern of the charge fragment topology in the dissociation of $^{10}$C and $^{12}$N nuclei is obtained for the first time. Contribution of the unbound nucleus decays to the cascade process $^{10}$C$rightarrow ^9$B$rightarrow ^8$Be is identified.
indent First results of the exposure of nuclear track emulsions in a secondary beam enriched by $^9$C nuclei at energy of 1.2 A GeV are described. The presented statistics corresponds to the most peripheral $^9$C interactions. For the first time a di
ssociation $^9$C $to3^3$He not accompanied by target fragments and mesons is identified.par
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 a
nd special features of their angular distributions are presented.
In the context of the search for triples of relativistic $alpha$-particles in the Hoyle state, the analysis of available data on the dissociation of the nuclei ${}^{12}$C, ${}^{16}$O and ${}^{22}$Ne in the nuclear emulsion was carried out. The Hoyle
state is identified by the invariant mass calculated from pair angles of expansion in $alpha$-triples in the approximation of the conservation of the momentum per nucleon of the parent nucleus. The contribution of the Hoyle state to the dissociation of ${}^{12}$C $to$ 3$alpha$ is 11%. In the case of the coherent dissociation of ${}^{16}$O $to$ 4$alpha$ it reaches 22% when the portion of the channel ${}^{16}$O $to$ 2${}^{8}$Be is equal to 5%.
Production of ensembles of $alpha$-particle triples associated with the Hoyle state (the second excited state of the ${}^{12}$C nucleus) in peripheral dissociation of relativistic ${}^{12}$C nuclei is studied. Stacks of nuclear track emulsion pellicl
es exposed to ${}^{12}$C with an energy from hundreds MeV to a few GeV per nucleon serve as the material for studies. The Hoyle state decays are reconstructed via measurement of emission angles of $alpha$ particles with the precision sufficient for identification of the unstable ${}^{8}$Be nucleus. The estimate of the contribution of Hoyles state to the ${}^{12}$C $to$ 3$alpha$ dissociation is 10-15%.
D. A. Artemenkov
,N. K. Kornegrutsa
,D. O. Krivenkov
.
(2011)
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"On a possible observation of dihelion in dissociation of relativistic $^9$C nuclei"
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Krivenkov Dmitry
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