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Phys. Rev. D 74, 092006 (2006) [8 pages]

Improved measurement of the branching fraction and energy spectrum of η from Υ(1S) decays

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O. Aquines et al. CLEO Collaboration
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Received 10 October 2006; published 27 November 2006; corrected 6 June 2007

We present an improved measurement of the η meson energy spectrum in Υ(1S) decays, using 1.2  fb-1 of data taken at the Υ(1S) center-of-mass energy with the CLEO III detector. We compare our results with models of the η gluonic form factor that have been suggested to explain the unexpectedly large BηXs rate. Models based on perturbative QCD fail to fit the data for large η energies, and thus an explanation outside the realm of the Standard Model or an improved understanding of nonperturbative QCD effects may be needed to account for this large rate.

© 2006 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevD.74.092006
DOI:
10.1103/PhysRevD.74.092006
PACS:
13.25.Gv, 13.25.Hw, 13.66.Bc

See Also

Publisher's Note: O. Aquines et al. CLEO Collaboration, Publisher’s Note: Improved measurement of the branching fraction and energy spectrum of η from Υ(1S) decays [Phys. Rev. D 74, 092006 (2006)], Phys. Rev. D 75, 119902 (2007).