Leptonic widths of high excitations in heavy quarkonia

Abstract

Agreement with the measured electronic widths of the $\psi (4040)$, $\psi (4415)$, and ${\rm Y}(11019)$ resonances is shown to be reached if two effects are taken into account: a flattening of the confining potential at large distances and a total screening of the gluon-exchange interaction at $r\text{ga}1.2$ fm. The leptonic widths of the unobserved ${\rm Y}(7S)$ and $\psi (5S)$ resonances: ${\Gamma }_{e^{+}{e}^{-}}({\rm Y}(7S))=0.11$ keV and $\Gamma (\psi (5S))\approx 0.54$ keV are predicted.

Comments: 11 pages revtex4