Sequential Decays of the Υ″
- 25 March 1991
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review Letters
- Vol. 66 (12), 1563-1566
- https://doi.org/10.1103/physrevlett.66.1563
Abstract
We have studied the decay chain Υ″→()γ→Υ′(Υ)γγ→μμ(ee)γγwith the CUSB II detector at the Cornell Electron Storage Ring. For a sample of 1.33× Υ″'s we find ≈400 events. We measure branching ratios for→Υ′(Υ)γ and, using calculated E1 rates, we derive total and hadronic widths of the states. From these widths we obtain values of in the range between 0.13 and 0.21, in agreement with other determinations. We observe the suppressed decay Υ″→γ. The measured branching ratio suggests that relativistic effects are important. We also determine the branching ratios for Υ″→Υ′ to be (1.3±0.4±0.2)% andΥ″→Υ to be (1.8±0.3±0.2)%. © 1991 The American Phsyical Society
Keywords
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