Measurement of Prominent eta Decay Branching Fractions

Abstract

The decay psi(2S) --> eta J/psi is used to measure, for the first time, all prominent eta-meson branching fractions with the same experiment in the same dataset, thereby providing a consistent treatment of systematics across branching fractions. We present results for eta decays to gamma gamma, pi+pi-pi0, 3 pi0, pi+ pi- gamma, and e+ e- gamma, accounting for 99.9% of all eta decays. The precisions for several of the branching fractions and their ratios are improved. Two channels, pi+ pi- gamma and e+ e- gamma, show results that differ at the level of three standard deviations from those previously determined.

11 pages postscript,also available through http://www.lns.cornell.edu/public/CLNS/2007/, Submitted to PRL

References in corpus (2)

• Big-Bang nucleosynthesis (Particle Data Group mini-review)
• The Cosmological Parameters 2006

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• Exclusive Measurement of the eta --> pi+ pi- gamma Decay
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• Measurement of the branching ratio and search for a CP violating asymmetry in the eta -> pi+pi-e+e-(gamma) decay at KLOE
• Measurements of Branching Ratios for $\eta$ Decays into Charged Particles
• Measurement of the eta-Meson Mass using psi(2S) --> eta J/psi
• A Re-evaluation of Evidence for Light Neutral Bosons in Nuclear Emulsions
• Study of ${\pi }^0$ and $\eta$ decays containing dilepton
• Observation of the Dalitz Decay $D_s^{\ast +}\to D_s^{+}{e}^{+}{e}^{-}$
• Measurement of the absolute branching fractions of Jpsi to gamma eta and eta decay modes
• Light hadron, Charmonium(-like) and Bottomonium(-like) states
• Hadronic Physics