Low-energy electric dipole response in 120Sn

Electric dipole strength in 120 Sn below the neutron threshold has been extracted from proton inelastic scattering experiments at Ep = 295 MeV and at forward angles including 0 . The strength distribution is very dierent from the results of a 120 Sn(; 0 ) experiment and peaks at an excitation energy of 8.3 MeV. The total strength corresponds to 2.3(2)% of the energy-weighted sum rule and is more than three times larger than what is observed with the (; 0 ) reaction. This implies a strong fragmentation of the E1 strength and/or small ground state branching ratios of the excited 1 states.