Measurement of the J/ψJ/\psi radiative decay into f0(1270)γf^0(1270)\gamma

The J/ψ decay modes f 0 (1270)γ and ρπ have been studied in e + e − collision at 3.1 GeV center of mass energy leading to the π + π − γ and π + π − π 0 final states. The f 0 γ decay branching ratio is measured to be (0.20 ± 0.07) × 10 −2 , a value comparable to the J/ψ radiative decay rates into the ηγ and η′γ channels. The J/ψ decay branching ratio into ϱπ is measured to be (1.6 ± 0.4) × 10 −2

Evidence for heavy leptons from anomalous μμe production in e+e^+e−e^− annihilation

Events of the type e + e − →μ ± +e ∓ + “nothing” have been observed in the magnetic detector PLUTO at the storage ring DORIS at DESY. The data support the hypothesis of the pair production of heavy leptons, and allow to determine decay parameters. Decay rates into muons and electrons are equal within error, and argue for a new lepton number of the heavy lepton

Measurement of the branching ratios for the decays J/ψJ/ψ (3.1) →→ fωf ω and J/ψJ/ψ (3.1) → BπBπ

Decays of the J/ψ (3.1) resonance into final states with four charged and one neutral pion have been investigated. We measured the branching ratios J/ ψ (3.1) → f ω /all = 0.40 ± 0.14)% and J/ ψ (3.1) → (B + π − + B − π + )/all = (0.28 ± 0.07)%

Inclusive production in e+e^+e−e^− annihilation in the energy range from 4.0 to 5.0 GeVeV

We report on inclusive production of J ψ (3.1)-mesons observed in e + e − -annihilation in the energy range s = 4.0–5.0 GeV . After substraction of the radiative tail of the ψ(3.7) direct production of the J ψ (3.1) is found to be in the order of 0.1% of the total hadronic cross section. No enhancements are seen at s = 4.03 GeV and 4.4 GeV. The level is in agreement with expectations from violation of the Zweig-rule