Description
Nuclei in the region of $^{80}$Zr have long been thought to exhibit strong nuclear deformation, and rapid changes in nuclear shape happen in this region of the nuclear chart. From spherical at N = 50, nuclei become strongly deformed in the N ≤ 40 region. Until now, studies focus on Yrast states and the observation of deformed bands in neutron-deficient Sr nuclei. Another way of studying these phenomena is through conversion electron spectroscopy, by which E0 transitions between two 0+ states can be measured. Low-lying 0$^{+}$ states and large E0 strengths are usually a hint of coexisting shapes becoming mixed [1] and their measure could very much help our understanding of the southern border of this region of deformation. Such low-lying 0$^{+}$ states have already been observed in neutron-deficient Kr and Se nuclei [2, 3] but a systematic study is still missing in Sr isotopes, approaching N = Z and the $^{80}$Zr nucleus, where multiple shape coexistence is expected [4]. One low-lying 0$^{+}$ state has been observed in $^{80}$Sr via $^{78}$Kr($^{3}$He, n) reaction at 1 MeV, but its decay to the ground-state was not [5] and could be related to a coexisting structure for which E0 information is missing. This LOI proposes to study 0$^{+}$ states in $^{82}$Sr and $^{80}$Sr, where E0 information is missing, down to $^{78}$Sr where no such states have been observed yet and everything is to be done.
[1] P. E. Garrett, M. Zielińska, and E. Clément, An experimental view on shape coexistence in nuclei, Progress in Particle and Nuclear Physics 124, 103931 (2022)
[2] E. Clément et al., Shape coexistence in neutron deficient krypton isotopes, Phys. Rev. C 75 054313 (2007)
[3] A. Ahmed et al., Level structure of $^{70}$Se, Phys. Rev. C 24 1486 (1981)
[4] T. R. Rodriguez, J. Luis Egido, Multiple shape coexistence in the nucleus $^{80}$Zr, Phys. Lett. B 705 255 (2011)
[5] W. P. Alford et al., A study of the (3He, n) reaction on isotopes of krypton, Nucl. Phys. A 330-1 77 (1979)