Hoyle state and unstable nuclei in relativistic nuclei dissociation

Oct 12, 2020, 4:45 PM


Oral report Section 2. Experimental and theoretical studies of nuclear reactions. Section 2. Experimental and theoretical studies of nuclear reactions


Andrei Zaitsev (Joint Institute for Nuclear Research)


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].

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.

Primary author

Andrei Zaitsev (Joint Institute for Nuclear Research)

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