Charmonium Decays of $Y(4260), psi(4160), and psi(4040)

TL;DR

This paper investigates charmonium decay modes of the Y(4260), psi(4160), and psi(4040) resonances using CLEO data, confirming known decays and discovering new decay channels with measured cross-sections.

Contribution

It provides the first observation of Y(4260) decays to pi0 pi0 J/psi and evidence for decay to K+ K- J/psi, expanding understanding of charmonium decay modes.

Findings

Confirmed Y(4260) --> pi+ pi- J/psi at 11σ significance

First observation of Y(4260) --> pi0 pi0 J/psi at 5.1σ

Evidence for Y(4260) --> K+ K- J/psi at 3.7σ

Abstract

Using data collected with the CLEO detector operating at the CESR e+e- collider at sqrt s = 3.97-4.26 GeV, we investigate 15 charmonium decay modes of the psi(4040), psi(4160), and Y(4260) resonances. We confirm, at 11$\sigma$ significance, the BaBar Y(4260) --> pi+ pi- J/psi discovery, make the first observation of Y(4260) --> pi0 pi0 J/psi (5.1 sigma), and find the first evidence for Y(4260) --> K+ K- J/psi (3.7 sigma). We measure e+e- cross-sections at sqrt s = 4.26 GeV as sigma(pi+ pi- J/psi) = 58 +12-10 +- 4 pb, sigma(pi0 pi0 J/psi) = 23 +12 -8 +- 1 pb, and sigma(K+ K- J/psi) = 9 +9 -5 +- 1 pb, in which the uncertainties are statistical and systematic, respectively. Upper limits are placed on other decay rates from all three resonances.