Single eta production in heavy quarkonia transitions

Abstract

The $η$ production in the $(n,n')$ bottomonium transitions $Υ(n) \to Υ(n') η, $ is studied in the method used before for dipion heavy quarkonia transitions. The widths $Γ_η(n,n')$ are calculated without fitting parameters for $n=2,3,4,5, n'=1$.Resulting $Γ_η(4,1)$ is found to be large in agreement with recent data.

10 pages