Study of nuclear interactions in 34Si, preliminary results from LISE2022 campaign

by Ozge Aktas, Postdoc at GANIL

According to the shell model, the nuclear shell gaps are one of the most important information for the nuclear structure and they are direct fingerprints of the nuclear interactions. The closed shells are well established for the stable nuclei, however, the experimental results show that the magic numbers are not universal over the nuclear chart. They vary with the ratio of protons and neutrons, and new ones evolve close to the neutron drip lines. ³⁴Si with 14 protons and 20 neutrons shows the characteristic properties of the double magic nucleus with a closed shell. The main characteristics for a double magic nucleus are a high 2⁺ state, low B(E2) value and clear drop in the neutron separation energy (Sn). ³⁴Si isotope was studied several times using different experimental methods, recent measurements were, through beta decay of ³⁴Al which produced with one neutron pickup and 3 proton removal from ³⁶S beam [1], and gamma-ray spectroscopy in the ISOLDE decay station via beta decays of ³⁴Al and ³⁴Mg [2,3].

In the LISE2022 campaign, e798 experiment was performed in GANIL in July 2022 using ³⁴Si beam at 55 MeV/u energy with thick ¹⁹⁷Au and ¹²C target. The first objective of the experiments was to study the deformed and spherical 2⁺ state and confirm the structure of the third 2⁺ state while measuring the B(E2) ratio and mixing ratio of the first and second 0⁺ states. The second objective was to measure the PDR through isoscalar and isovector probes. As an experimental setup, LISE+Exogam+PARIS+Silicon Strips and ZDD detector systems were used for identification and trajectory reconstructions. In this seminar, I will present the preliminary results from this experiment while focusing mostly on nuclear interactions and mass identifications on ZDD.

[1] F. Rotaru et al. Phys. Rev. Lett. 109, 092503 (2012)
[2] R. Lica  et al. Phys. Rev. C 95, 021301 (2017)
[3] R. Lica et al. Phys. Rev C 100, 034306 (2019)