Search for giant spin-flip transitions in 90Zr and 208Pb☆

Abstract We have searched for the giant magnetic dipole resonance in 90 Zr and an associated state in 208 Pb. Among the experimental techniques employed in this search was the detection of inelastically scattered protons in coincidence with ground-state de-excitation γ-rays, No state in 90 Zr up to an excitation of 10.5 MeV or in 208 Pb between 5.0 to 6.0 MeV was observed with the desired characteristics. In 90 Zr, heretofore unidentified levels at 5.51, 5.89 and 6.42 MeV were determined to have J π = 1 − . In 208 Pb J π = 1 − states were observed at 5.29, 5.51 and 5.94 MeV. The implications of our observations are discussed.