Examination of nuclear chirality with a magnetic moment measurement of the I=9 isomeric state in Cs-128

The g factor of the isomeric I = 9(+) bandhead of the yrast states in Cs-128 is obtained from the time differential perturbed angular distribution measurement performed with the electromagnet at IPN Orsay. An external magnetic field of 2.146 T at the target position was attained with GAMIPE reaction chamber surrounded by four high-purity germanium detectors, of which two were low-energy photon spectrometer type. The results are in accordance with pi h(11/2) circle times nu h(11/)(2)(-1) I = 9(+) bandhead assignment and are discussed in the context of chiral interpretation of the Cs-128 nucleus as a composition of the odd proton, odd neutron, and even-even core with their angular momentum vectors. The obtained g-factor value was compared with predictions of the particle-rotor model. The experimental g factor corresponds to the nonchiral geometry of the isomeric bandhead. This observation indicates the existence of the chiral critical frequency in Cs-128 and may explain the absence of the chiral doublet members for I < 13<(h)over bar>.