Lifetimes in ¹²⁶Te from in-beam (n,n′ γ) measurements

The excited levels of ¹²⁶Te have been studied using the (n,n' γ) reaction. Excitation functions, γγ coincidences, angular distributions, and Doppler shifts were measured for γ rays from levels up to an excitation energy of 3.2 MeV; multipole-mixing and branching ratios and transition rates were deduced. Experimental values of electromagnetic transition rates were compared with the anharmonic vibrator model, the general collective model, the neutron-proton interacting boson model with intruder mixing, and particle-core coupling model calculations. No advantage is found in using an intruder description for the low-spin states of ¹²⁶Te. All models used reproduce some features of the level scheme and many transition rates, but the particle-core coupling model was found to have better overall success describing the observed properties of this nucleus.