Magnetic moment of a mixed-symmetry state of Zr nuclei

Mixed-symmetric states are quadrupole collective states with anti-symmetric parts in their pn wave function. Breaking of the proton-neutron (pn) symmetry was discussed for $^{92}$Zr within the IBM-2, the shell model (SM), and the quasiparticle phonon model (QPM). The models differ in quantifying the pn symmetry breaking, which leads to substantial differences in the predictions for the g factor of the one-phonon $2^+_{1, {\rm ms}}$ state with predominantly mixed-symmetry character. The g factor of this state is difficult to measure due to its short lifetime. First measurements in Zr isotopes have been performed at WNSL using the transient field technique. Results will be compared to model predictions. Work supported by USDOE grants DE-FG02-91ER-40609, DE-FG52-05NA25929, and DE-FG02-88ER40417, U.S. NSF (RU and SB), and DFG under Br 799/12-1.