Nuclear excitation in muonic 209Bi

Abstract The hyperfine spectra of muonic L and K X-rays of 209 Bi have been reanalyzed by taking into account the resonance processes and the observed isomer shifts in addition to the M1 and the E2 interaction. The M1 and E2 hyperfine structure constants of the 1s, 2p and 3d muonic states and the nuclear static moments of the excited states 15 2 + and 9 2 + are determined from the best fits to the experimental spectra. The hfs constants and the M1 moments are in good agreement with theoretical predictions from the core excitation model. The quadrupole moment of the ground state remains to be 20% higher than that determined by the atomic beam method. A plausible interpretation is that this discrepancy might be due to the deformation of the lead core.