Speaker
Description
The magicity of N=20 in the vicinity of Ne, Na, and Mg isotopes vanishes due to pf-shell intruder configuration, which is called 'island of inversion' [1-3]. In recent years, shell evolution of Ne isotopes in this region is emerging topic of interest [4,5]. Nevertheless, there is no observed state of $^{33}$Ne.
It is only known that $^{33}$Ne is unbound nuclei [6] and the 1n separation energy $S_{n}$ is only predicted to -0.9 MeV [7].
The experiment was carried out at the RIBF in RIKEN. The secondary beam of $^{34}$Na at 264 MeV/nucleon was provided by BigRIPS [8] and impinged on the carbon reaction target. After the one-proton knockout reaction of $^{34}$Na, $^{33}$Ne was produced and immediately decayed into $^{32}$Ne and a neutron. The invariant mass spectrum of $^{32}$Ne + n system was reconstructed by measurement of fragments and neutrons using SAMURAI spectrometer [9]. In this presentation, details of analysis and preliminary results of $^{32}$Ne + n invariant mass spectrum will be discussed.
[1] Z. Elekes et al., Phys. Rev. C 73, 044314 (2006).
[2] P. Doornenbal et al., Phys. Rev. Lett. 103, 032501 (2009).
[3] P. Doornenbal et al., Phys. Rev. C 81, 041305 (2010).
[4] T. Nakamura et al., Phys. Rev. Lett. 112, 142501 (2014).
[5] I. Murray et al., Phys. Rev. C 99, 011302 (2019).
[6] M. Notani et al., Phys. Lett. B 542, 49 (2002).
[7] G. Audi, H. Wapstra, and C. Thibault, Nucl. Phys. A 729, 337 (2003).
[8] T. Kubo, Nucl. Inst. and Meth. B 204, 97 (2003).
[9] T. Kobayashi et al., Nucl. Inst. and Meth. B 317, 294 (2013).
