Speaker
Description
Since nuclear matter is composed of two Fermi particles, protons and neutrons, the equation of state(EOS) of nuclear matter has a term that depends on the density difference between the two, which is called the symmetry energy. From previous studies, it is known that the first-order density dependence of the symmetry energy $L$ is closely related to the thickness of the neutron skin $r_{\rm np}$ [1].
In this study, interaction cross sections ${\sigma}_{\rm{I}}$ for $^{58-77}$Ni on a carbon target at 250 MeV/nucleon have been measured to derive matter radii. Recently, the charge radii of Ni isotopes up to mass number 70 were measured by isotope shift method [2]. So, we can derive the neutron skin thickness $r_{\rm np}$ in the region of $A$ = 58 to 70. The experiment was performed at the Radioactive Isotope Beam Factory(RIBF) at RIKEN by using the BigRIPS fragment separator.
In this presentation, we discuss the mass-number dependence of the matter radii derived from the measured interaction cross sections using the Glauber model.
[1] M. Centelles et al., Phys. Rev. Lett. 102, 122502 (2009).
[2] S. Malbrunot-Ettenauer et al., Phys. Rev. Lett. 128, 022502(2022).