Phys. Rev. Lett. 84, 26 - 30 (2000)

Search for Rare and Forbidden η Decays

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R. A. Briere et al. (CLEO Collaboration)
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Received 22 July 1999; revised 4 November 1999

We have searched for rare and forbidden decays of the η meson in hadronic events at the CLEO II detector. The search is conducted on 4.80 fb-1 of e+e- collisions at 10.6 GeV center-of-mass energy at the Cornell Electron Storage Ring. We find no signals, and set 90% confidence level upper limits of their branching fractions: Be+e-η)<2.4×10-3, Be+e-π0)<1.4×10-3, Be+e-γ)<0.9×10-3, and Beμ)<4.7×10-4. We also fit the matrix element of the η→π+π-η Dalitz plot with the parametrization |M|2  =  A|1+αy|2, where y is a linear function of the kinetic energy of the η, and find Re (α)  =  -0.021±0.025.


©2000 The American Physical Society

URL: http://link.aps.org/doi/10.1103/PhysRevLett.84.26
DOI: 10.1103/PhysRevLett.84.26
PACS: 14.40.Cs, 11.30.Er, 13.40.Hq

* Permanent address: Yonsei University, Seoul 120-749, Korea.
Permanent address: University of Cincinnati, Cincinnati, OH 45221.

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