Observation Of Chi-B Production In The Exclusive Reaction Epsilon'-]Gamma-Chi-B-]Gamma-Gamma-Epsilon-]-Gamma-Gamma(E+E-Or-Mu+Mu-)

We report on the observation of 1 3 P J ( χ b ) production in the reaction ϒ ′→ γχ b → γγϒ → γγ (e + e − or μ + μ − ). The data were recorded with the nonmagnetic CUSB detector at the Cornell Electron Storage Ring, CESR. We observe 124 γγ events with either an electron or muon pair in the final state. In the γγ correlation plot about 40% of the events cluster around (120, 430) MeV.