Signature for g bosons from medium energy proton scattering experiments

We apply the recently developed algebraic (1/N expansion) scattering formalism to medium energy proton scattering from 154Sm and 176Yb. The nuclear structure effects in this formalism are described by the interacting boson model generalized to arbitrary interactions and types of bosons i.e. s,d,g, etc. We find that, in the sd boson model, a consistent description of cross sections is possible only for the 0+ and 2+ states. The failure of the model with regard to the 4+ states indicates that the effective hexadecapole operator used in the sd model is inadequate. In contrast, the data for scattering to the 0+, 2+ and 4+ states could be consistently described in the sdg boson model. The spectroscopic data for the low-lying levels usually can not distinguish between the sd and sdg models due to renormalization of parameters, and one has to look at high spin or energy data for evidence of g bosons. The inelastic proton scattering experiments, on the other hand, directly probe the wave functions, and hence could provide a signature for g bosons even in the ground band states