Search for decays of the 9^{9}B nucleus and Hoyle state in 14^{14}N nucleus dissociation

First results of an analysis to determine contribution of decays of the unstable $^{8}$Be and $^{9}$B nuclei and the Hoyle 3$\alpha$-state to dissociation of $^{14}$N $\to$ 3He (+H) are presented. As the research material, layers of nuclear track emulsion longitudinally exposed to 2.9 $A$ GeV/$c$ $^{14}$N nuclei with at the JINR Nuclotron. Under the assumption that the He and H fragments retain momentum per nucleon of the primary nucleus, these unstable states are identified by the invariant mass calculated from the emission angles of the fragments.Comment: Article materials were presented in the report by A.A. Zaitsev at LXX International conference Nucleus - 2020, https://indico.cern.ch/event/839985/contributions/3985257 To be published in journal "Physics of Particles and Nuclei

Prospects of searching for unstable nucleus states in relativistic nuclear fragmentation

The article is dedicated to the experimental study in the relativistic approach to the problems of nuclear cluster physics for the prospects of the \href{http://becquerel.jinr.ru/}{BECQUEREL} experiment. The nuclear emulsion method applied in this experiment makes it possible to study thoroughly the relativistic final states in the fragmentation of nuclei. The focus of the presented research is the dynamics of emergence of the $^{8}$Be nucleus and the Hoyle state, as well as the search for the 4$\alpha$-particle condensate decaying via the above nuclear states. In this context, the analysis of exposure to $^{84}$Kr nuclei at 950 MeV/nucleon is shown. As a continuation of the study of light nuclei, we have demonstrated the search for the isobar-analogue state of the $^{13}$N nucleus in the fragmentation of $^{14}$N nuclei at 2 GeV/nucleon.Comment: Presented at XVth Cherenkov Readings https://x4u.lebedev.ru/che2022/announce_ru-RU.html; submitted to Physics of Atomic Nuclei