bb-bar spectroscopy from the Upsilon (3S) state.

Using the CUSB-II detector at CESR we have observed electric dipole transitions between the γ and χ b states, both in exclusive and inclusive channels. We have measured their branching ratios and find B(γ(3S)χ b (2P 2,1,0 ) γ)=(11.1±0.5±0.4)%, (11.5±0.5±0.5)%, (6.0±0.4±0.6)%. We have measured the center of gravity of the χ b (2P) states to be (10259.5±0. 4±1.0) MeV and their fine-structure mass splittings to be (13.5±0.4±0.5) MeV between the J=2 and J=1 states and (23.5±0.7±0.7) MeV between J=1 and J=0, leading to a fine-structure ratio of 0.574±0.024±0.02