Non-yrast spectroscopy for a possible K-mixing in ^155Gd

A recent Coulomb excitation (COULEX) result on ^155Gd, reported by Kidera et al. [1], has shown an interesting experimental observation that a rotational band 3/2^+[651] with the positive parity different from the ground state band 3/2^-[521] was populated with anomalously large intensity. It is conceivable that possible existence of intermediate bands can be K-mixed and these bands side-feed the 3/2^+[651] band. In order to search for such candidate bands, we performed the ^154 Sm(α,3nγ)^155Gd coincidence experiment at the beam energy of 33 MeV delivered by the SF cyclotron at Center for Nuclear Study, University of Tokyo. We found three intermediate rotational bands that are linked to the 3/2^+[651] band. In addition, more than ten new gamma rays belonging to known bands were also found. We shall report our result with additional information of spin-parity assigned to these new bands and discuss in the context of K-mixing. [1] M. Kidera et al., J. Phys. Soc. Japan 66, 285 (1997).