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Radiative decays of the upsilon (2S) resonance

Technical Report ·
DOI:https://doi.org/10.2172/6827322· OSTI ID:6827322
The Crystal Ball Detector at DORIS II was used to study radiative decays of the upsilon (2S) resonance with more than twice the previously available data. The inclusive photon spectrum of hadronic upsilon (2S) decays and the exclusive channel upsilon (2S) ..-->.. ..gamma gamma.. upsilon (1S) ..-->.. ..gamma gamma.. l/sup +/l/sup -/ were analyzed. In the inclusive spectrum three significant photon lines at energies of E..gamma../sub 1/ = (108.2 +- 0.7 +- 4) MeV, E..gamma../sub 1/ = (127.1 +- 0.8 +- 4) MeV and E..gamma../sub 3/ = (160.0 +- 2.4 +- 4) MeV with branching fractions of (6.0 +- 0.7 +- 0.9)%, (6.6 +- 0.8 +- 1.0)%, (2.6 +- 0.7 +- 0.8)% respectively were measured. The lines are consistent with being transitions from the upsilon (2S) to the /sup 3/P/sub 2/, /sup 3/P/sub 1/ and /sup 3/P/sub 0/ states. In addition a line at E..gamma.. approx. 427 MeV was observed which is interpreted as transitions from the /sup 3/P/sub 2/ /sub 1/ states to the upsilon (1S). 17 references.
Research Organization:
Harvard Univ., Cambridge, MA (USA). Dept. of Physics; Stanford Linear Accelerator Center, CA (USA)
DOE Contract Number:
AC03-76SF00515; AC02-76ER03064
OSTI ID:
6827322
Report Number(s):
SLAC-PUB-3325; CONF-8403121-2; ON: DE84011858
Country of Publication:
United States
Language:
English