Fragmentation of mixed-symmetry excitations in stable even-even tellurium nuclei

The lowest six excited 2+ levels of the even-even Te122-130 nuclei have been investigated using γ-ray spectroscopy following inelastic neutron scattering. These levels have been identified and their decay properties have been characterized from γ-ray excitation functions and γ-ray angular distributions; additionally, lifetimes of these levels have been deduced using the Doppler-shift attenuation method. Electromagnetic transition rates and E2/M1 multipole mixing ratios from the 2x+[x=2-6]→21+ transitions have been examined to identify the lowest mixed-symmetry states in these nuclei. In each nucleus, the mixed-symmetry strength appears to be fragmented between more than one level. The summed M1 strength from the 2x+ [x=2-6] states to the 21+ level agrees rather well with neutron-proton interacting boson model predictions in the U(5) or O(6) limits for these Te nuclei.