Effective Charges in the fp Shell

Following the heavy-ion fusion-evaporation reaction 32S+24Mg at 95 MeV beam energy the lifetimes of analogue states in the Tz=±1/2 A=51 mirror nuclei 51Fe and 51Mn have been measured using the Cologne plunger device coupled to the GASP γ-ray spectrometer. The deduced B(E2;27/2-→23/2-) values afford a unique opportunity to probe isoscalar and isovector polarization charges and to derive effective proton and neutron charges, εp and εn, in the fp shell. A comparison between the experimental results and several different large-scale shell-model calculations yields εp∼1.15e and εn∼0.80e.