Physical Review D 74,9 (2006) 092006;
We present an improved measurement of the eta(') meson energy spectrum in Upsilon(1S) decays, using 1.2 fb(-1) of data taken at the Upsilon(1S) center-of-mass energy with the CLEO III detector. We compare our results with models of the eta(') gluonic form factor that have been suggested to explain the unexpectedly large B ->eta X-'(s) rate. Models based on perturbative QCD fail to fit the data for large eta(') 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.
b-decays;; eta';; detector
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