Structure of high spin states in ¹⁰⁴Sn: E2 and E3 polarization of the ¹⁰⁰Sn core

High spin states in ¹⁰⁴Sn were identified in the reaction ⁵⁸Ni(⁵⁰Cr, 2p2n) at 200 and 205 MeV beam energies. The γ-ray energies, intensities, multipolarities, and lifetimes of high spin states were measured with the GASP spectrometer array in combination with a plunger apparatus by means of the recoil distance Doppler shift method. The deduced level scheme and transition probabilities are compared to the results of large-scale shell model calculations using three independent two-body interactions. The agreement of the level energies is satisfactory, except for a cascade of dipole transitions at high spins. The general good agreement found for E2 transition strengths implies a large effective neutron polarization charge. The shell-model calculations do not account for the measured enhanced E3 transitions for which a core excited octupole phonon admixture is indicated.