Transition charge densities of low-lying collective states in even Zn isotopes

Abstract

The inelastic electron scattering cross sections for the quadrupole transitions to the 2 1 + and 2 2 + states in the even Zn isotopes 64Zn, 66Zn and 68Zn and for the hexadecapole transition to the 4 + 1 state in 64Zn have been measured in a momentum transfer range up to q = 2.2 fm −1. In the frame-work of the vibrational model these states are considered as one- and two-quadrupole-phonon states. The measurements are characterized by high statistical accuracy and by an overall resolution of δE/ E 0 = 10 −3 which permitted separation of almost all members of the two-phonon triplet. The measured cross sections are analyzed with phenomenological models as well as with a Fourier-Bessel expansion of the transition charge density. The latter analysis yields realistic error bands for the transition charge densities and model-independent values for the reduced transition probabilities and transition radii.