Speaker
Description
The phenomenon of dissociation of relativistic nuclei observed with a unique completeness in the nuclear track emulsion (NTE) makes it possible to study ensembles of nucleons and lightest nuclei of interest to nuclear cluster physics and astrophysics [1]. The advantages of the NTE technique include a record space resolution in determining emission angles for recognition relativistic ${}^{8}$Be and ${}^{9}$B decays among the He and H projectile fragments. The decays are identified by the invariant mass $M^*$ defined by the sum of all products of 4-momenta $P_i$ of relativistic fragments He and H. The components $P_i$ are determined by the fragment emission angles under the assumption of conservation a projectile momentum per nucleon. Recently, in the events of relativistic dissociation of ${}^{9}$Be, ${}^{10}$B, ${}^{10}$C, ${}^{11}$C nuclei were identified unstable ${}^{8}$Be and ${}^{9}$B nuclei by invariant mass approach [2]. The successful identification of ${}^{9}$Be nuclei allowed us to cross to the problem of identifying triples of alpha particles in the Hoyle state (HS) in the dissociation of relativistic nuclei. Production of $\alpha$-particle triples in the HS in dissociation of ${}^{12}$C nuclei at 3.65 and 0.42 $A$ GeV in NTE was investigated [3]. Contribution of the HS to the dissociation ${}^{12}$C $\to$ 3$\alpha$ is (11 $\pm$ 3) %. Analysis of data on coherent dissociation ${}^{16}$O $\to$ 4$\alpha$ at 3.65 $A$ GeV is revealed the HS contribution of (22 $\pm$ 2) %. These observations indicate that it is not reduced to the unusual ${}^{12}$C excitation and, like ${}^{8}$Be, is a more universal object of nuclear molecular nature. Reanalysis of data on dissociation of heavier nuclei (Ne, Si, Kr and Au) pointed out to significant contribution of HS in the n$\alpha$-channels. The analysis of the NTE layers exposed to relativistic ${}^{14}$N nuclei is resumed in the HS context. Video collection of relativistic nuclei dissociation events in NTE obtained using a microscope and a digital camera can be found [4].
References:
1. P.I.Zarubin // Lect. Notes in Physics, Clusters in Nuclei, 2014. V.875(3) P.51; arXiv: 1309.4881.
2. D.A.Artemenkov, A.A.Zaitsev, P.I. Zarubin // Phys. Part. Nucl. 2017. V.48 P.147; arXiv:1607.08020.
3. D.A.Artemenkov et al. // Rad. Meas. 2018. V.119. P.119; arXiv:1812.09096.
4. The BECQUEREL Project. http://becquerel.jinr.ru/movies/movies.html.
