First observation of psi(2S)-->K_S K_L

Abstract

The decay psi(2S)-->K_S K_L is observed for the first time using psi(2S) data collected with the Beijing Spectrometer (BESII) at the Beijing Electron Positron Collider (BEPC); the branching ratio is determined to be B(psi(2S)-->K_S K_L) = (5.24\pm 0.47 \pm 0.48)\times 10^{-5}. Compared with J/psi-->K_S K_L, the psi(2S) branching ratio is enhanced relative to the prediction of the perturbative QCD ``12%'' rule. The result, together with the branching ratios of psi(2S) decays to other pseudoscalar meson pairs (π^+π^- and K^+K^-), is used to investigate the relative phase between the three-gluon and the one-photon annihilation amplitudes of psi(2S) decays.

5 pages, 4 figures, 2 tables, submitted to Phys. Rev. Lett

References in corpus (7)

• A possible hadronic excess in psi(2S) decay and rho-pi puzzle
• On Large Final-State Phases in Heavy Meson Decays
• Phases and Amplitudes in Inclusive $\Psi$ and ${\Psi }^{\prime }$ Decays
• A Measurement of Psi(2S) Resonance Parameters
• Improved measurement of the branching ratio of J/psi-->K_S K_L
• Relative phase between strong and electromagnetic amplitudes in psi(2S) to 0- 0- decays
• Psi(2S) two- and three-body hadronic decays

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