Tue·Jun 21, 2022Tuesday·June 21, 2022

1. 01*

   Nuclei near and at the proton dripline

   Marek Pfützner🇵🇱 · Chiara Mazzocchi

   Nuclei in the vicinity of the proton dripline and beyond it are a fascinating realm within the chart of nuclei. In this chapter the main phenomena that characterize this domain and are not to be found elsewhere are explored. While moving away from the $\beta$-stability valley towards the proton dripline, phenomena like very exotic decay modes such as $\beta$-delayed (multi-) particle emission, and proton-, or two-proton radioactivity are encountered. Landmark nuclei are here two isotopes with magic proton and neutron numbers, ${}^{48}$Ni and ${}^{100}$Sn. Moreover, proton-rich nuclei ($N<Z$) display other interesting features, like breaking of isospin symmetry with consequent asymmetry in the energy spectra between mirror nuclei, the so-called Thomas-Ehrmann shift, or the phenomenon of proton-halo. Last but not least, nuclei close to the proton dripline play a very important role in nucleosynthesis, since they take part in the rapid-proton capture process and their properties are crucial in defining the flow followed and its termination close to ${}^{100}$Sn.

   nucl-exnucl-th1 citation
2. 02*

   Search for possible alpha-condensate states in ${}^{20}$Ne

   A.S. Demyanova (1) · A.N. Danilov (1) · S.A. Goncharov (2) · V.I. Starastsin (1,3) · T.I Leonova (1,3) ((1) National Research Centre Kurchatov Institute, Moscow, Russia, (2) Lomonosov Moscow State University, Moscow, Russia, (3) National Research Nuclear University MEPhI, Moscow, Russia)

   The root mean square radii of ${}^{20}$Ne in the short-lived excited states were experimentally deduced for the first time from the analyses of $\alpha$+${}^{20}$Ne diffraction scattering. Differential cross sections of the elastic and inelastic $\alpha$+${}^{20}$Ne scattering in the incident energy range from a few MeV/nucleon up to 100 MeV/nucleon were analyzed by the modified diffraction model. No significant radius enhancement for the members of K${}^{\pi }$ = 0${}_1^{+}$ and K${}^{\pi }$ = 2${}^{-}$ bands in comparison with the ground state was observed. At the same time 20 % radius enhancement was obtained for the K${}^{\pi }$ = 0${}_1^{-}$ band members. Moreover, for the 0${}_2^{+}$ state located above $\alpha$-emission threshold increased radius was observed. This result can speak in favor of possible $\alpha$-condensate structure of the 0${}_2^{+}$ state and can be considered as a possible analog of the famous 7.65-MeV 0${}_2^{+}$ Hoyle state of ${}^{12}$C.

   nucl-exnucl-th0 citations
3. 03*

   Prospects of searching for unstable nucleus states in relativistic nuclear fragmentation

   D.A. Aretemenkov · V. Bradnova · O.N Kashanskaya · N.V. Kondratieva · N.K. Kornegrutsa · E. Mitsova · N.G. Peresadko · V.V. Rusakova · R. Stanoeva · A.A. Zaitsev🇷🇺 · P.I. Zarubin🇷🇺 · I.G. Zarubina

   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.

   nucl-exnucl-thPhys.Atom.Nucl.(2022)·4 citations
4. 04*

   Magnetic quadrupole transitions in the relativistic energy density functional theory

   G. Kružić · T. Oishi🇭🇷 · N. Paar🇭🇷

   Background: Magnetic quadrupole (M2) excitation represents a fundamental feature in atomic nucleus associated to nuclear magnetism induced by spin and orbital transition operator. So far it has only been investigated within the non-relativistic theoretical approaches, and available experimental data are rather limited. Purpose: We aim to investigate the properties of M2 transitions in closed and open-shell nuclei using the framework of relativistic nuclear energy density functional. The calculated M2 transition strengths could be used to constrain the quenching of the spin gyromagnetic factors. Methods: The M2 excitations are described using the relativistic quasiparticle random phase approximation (RQRPA) with the residual interaction extended with the isovector-pseudovector term. Results: The M2 transition strength distributions are described and analyzed for closed and open shell nuclei. The results are compared with available experimental data and the strength missing from the experiment is discussed. The evolution of M2 transition properties has been investigated within the ${}^{36-64}\mathrm{Ca}$ isotope chain. Conclusion: The main M2 transitions have rather rich underlying structure and their collectivity increases with the mass number due to larger number of contributing particle-hole configurations. Pairing correlations in open shell nuclei have strong effect, causing the M2 strength reduction and shifting of the centroid energies to higher values. The analysis of M2 transition strengths indicate that considerable amount of experimental strength may be missing, mainly due to limitations to rather restricted energy ranges. The calculated M2 strengths for Ca isotopes, together with the future experimental data will allow constraining the quenching of the $g$ factors in nuclear medium.

   ↳ nucl-thnucl-exEPJA(2023)·6 citations
5. 05*

   Cosmogenic background study for a 100Mo-based bolometric demonstration experiment at China JinPing underground Laboratory

   W. Chen · L. Ma · J. H. Chen · H. Z. Huang · Y. G. Ma

   We perform simulation study for a 10-kg ${}^{100}$Mo-based bolometeric demonstration experiment for neutrinoless double-beta decay ($0\nu \beta \beta$) search at China JinPing underground Laboratory (CJPL). Cosmogenic production of radionuclides in ${}^{100}$Mo-enriched lithium molybdate crystals and copper components of the detector system are studied using Geant4 toolkit based on the simulated cosmic ray data from the CRY library. Background energy spectra of the cosmogenic radionuclides including ${}^{56}$Co, ${}^{82}$Rb and ${}^{88}$Y which are harmful for the ${}^{100}$Mo-based $0\nu \beta \beta$ experiment are investigated. We then evaluate the total cosmogenic background level in the ${}^{100}$Mo $0\nu \beta \beta$ search energy region of interest (ROI) for the demonstration experiment. After one year of cooling down underground, the residual background contribution is found to be 1.8$\times$10${}^{-6}$ cts/kg/keV/yr and 3.3$\times$10${}^{-4}$ cts/kg/keV/yr from crystals and copper components, respectively. Furthermore, underground cosmogenic activation of copper and lithium molybdate crystal is calculated based on the simulation spectra of neutron and proton in CJPL. The underground cosmogenic background is found to be negligible in the ROI.

   ↳ physics.ins-dethep-exnucl-exNucl.Sci.Tech.(2023)·12 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.