Collectivity of neutron-rich Ti isotopes

Abstract

The structure of the neutron-rich nucleus ${}^{58}$Ti was investigated via proton inelastic scattering in inverse kinematics at a mean energy of 42.0 MeV/nucleon. By measuring the deexcitation $\ensuremath{\gamma}$ rays, three transitions with the energies of 1046(11) keV, 1376(18) keV, and 1835(27) keV were identified. The angle-integrated cross section for the 1046-keV excitation, which corresponds to the decay from the first 2${}^{+}$ state, was determined to be 13(7) mb. The deformation length ${\ensuremath{\delta}}_{p,{p}^{\ensuremath{'}}}$ was extracted from the cross section to be ${0.83}_{\ensuremath{-}0.30}^{+0.22}$ fm. The energy of the first 2${}^{+}$ state and the ${\ensuremath{\delta}}_{p,{p}^{\ensuremath{'}}}$ value are comparable to the ones of ${}^{56}$Ti, which indicates that the collectivity of the Ti isotopes does not increase significantly with neutron number until $N=36$. This fact indicates that ${}^{58}$Ti is outside of the region of the deformation known in the neutron-rich nuclei around $N=40$.