Beta decay and nuclear structure: Rb86

It was aimed to gain information on the nuclear structure of Rb86 by invetigation of the 2- → 2+ beta transition. For this purpose the energy dependence of the beta gamma angular correlation and the angle dependence of the beta gamma circular polarization correlation have been measured. A novel experimental set-up has been used for the angular correlation measurement allowing a simultaneous determination of the anisotropy coefficients A2 and A4 under considerable reduction of systematical errors. For the polarization correlation measurement an unusual experimental arrangement has been applied providing the possibility of simultaneos observation under four different angles. Employing additional data on shape factor measurements and energy dependent circular polarization correlations from other authors the nucleare structure of the 2 state in Rb86 and the 2+ first excited state in Sr86 have been evaluated. For the latter purpose the unified model with weak coupling has been chosen. (orig.)