Magnetic dipole strength in 128Xe and 134Xe in the spin-flip resonance region

The magnetic dipole strength in the energy region of the spin-flip resonance has been investigated in {128}Xe and {134}Xe using quasi-monoenergetic and linearly polarized gamma-ray beams at the HI gamma S facility in Durham, USA. Absorption cross sections were deduced for the electric and magnetic Dipole distributions separately for various intervals of excitation energy, including the strength of states in the unresolved quasi-continuum. Spin-flip like resonance structures were found in the magnetic dipole strength distribution around an excitation energy of 8 MeV. The E1 strength distributions deduced from the present experiments are compatible with the data of an experiment using bremsstrahlung that are based on simulations of statistical gamma-ray cascades. The experimental E1 and M1 strengths are compared with phenomenological approximations and with deformed-basis quasiparticle-random-phase-approximation predictions.