Research Papers in Physics and Astronomy


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Published by American Physical Society. Phys. Rev. Lett. 80, 2762 (1998). Permission to use. Copyright © 1998 American Physical Society.


We have searched for the rare decay of the η meson η→e+e- using the CLEO II detector. The η’s were produced in e+e- collisions with 10 GeV center-of-mass energy at the Cornell Electron Storage Ring (CESR). We find with 90% confidence the upper limit on the branching fraction B (η→e+e-)<7.7×10-5. The application of conventional elementary particle theory to this decay predicts a branching fraction of about 10-9.

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