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32 pp. (1977).

19 pp. (1976).

58 pp. (1978).

47 pp. (1975).

46 pp. (1978).

Physics letters / B 66(5), 489 - 492 (1977). doi:10.1016/0370-2693(77)90594-9, The decay of J/ψ (3.1) into final states containing no charged particles has been studied experimentally. The partial decay width for the observed neutral decays is (470 ± 160) eV. The decay modes J/ ψ → γη → 3 γ and J/ ψ γη ′ → 3 γ are identified and the branching ratios J ψ → γη J ψ → all = (1.3 ±0.4) × 10 −3 , and J ψ → γη′ J ψ → γη = 1.8 ±0.8 , are derived. Upper limits for the decay modes J/ ψ → γπ 0 and J/ ψ → γγ are given., Published by North-Holland Publ., Amsterdam

(1977). doi:10.1016/0370-2693(77)90115-0, The three photon final state produced in e + e − collisions at 3.6 GeV and at the mass of the ψ′ resonance has been measured using the nonmagnetic part of the double arm spectrometer DASP. A total of 31 events is observed outside the resonance region compared to 35.1 events predicted from QED. At the mass of the ψ′ 49 events are observed compared to 37.2 events expected from QED. Limits on radiative decays via intermediate states are given.

21 pp. (1978)., Decays of the heavy lepton τ have now been observed in e+e− ‐ collisions at the energy of the ψ′‐resonace, which results in an improved mass determination Mτ=1.807±0.020 GeV. For the τ‐life‐time a new upper limit of ττ?3.5⋅10−12 sec. is given. The evidence for the decay τ→νπρ has been strengthened, and the πρ‐system is found to be in an S‐wave state with JP=1+, proving the axial vector component in the leptonic coupling of the τ to hadrons. The branching ratio is given with BR(τ−→νπ−ρ0) =0.050±0.015. The total hadronic cross section agrees within errors with the quarksum rule including QCD‐corrections. The production and decay distributions of the decay J/ψ→f0γ have been measured and found to agree well with a QCD calculation based on the exchange of two gluons.

(1978). doi:10.1016/0370-2693(78)90183-1, The cross sections for e + e − → e + ( μ + + non showering track + any photons have been measured for cm energies between 3.1 GeV and 5.2 GeV. We observe τ -pair production below the thresholdfor charm production and determine the τ mass to be 1.807 ± 0.020 GeV from a fit to the energy dependence of the cross section. The ration of the leptonic branching ratios B μ / B e = 0.92 ± 0.32 is consistent with eμ-universality. The following branching ratios are determined for a V-A coupling: B(τ → ν τ e ν ) = B(τ → ν τ μ ν ) = 0.182 + 0.028 . B ( τ → ν τ + charged hadron + any photons) = 0.29 ± 0.11, B ( τ → ν τ + three or more charged hadrons + any photons) = 0.35 ± 0.11.

25 pp. (1976).

25 pp. (1975).

(1977). doi:10.1016/0370-2693(77)90114-9, The three photon final state produced in e + e − collisions has been measured at the mass of the J ψ resonance using the nonmagnetic part of the double arm spectrometer DASP. The decays J ψ → ηγ, η'γ and π o γ were observed and their branching ratios are given. A four standard deviation signal was observed in the γγ mass spectrum at a mass of (2.83 ± 0.03) GeV. An upper limit is given for the direct decay J ψ → 3γ .

58 pp. (1976).

14 pp. (1977).

11 pp. (1975).

(1977). doi:10.1016/0370-2693(77)90554-8, We propose to study the decay ψ ′ → γπ + π − X (2.83) for a better understanding of the nature of the χ (3.45) and X(2.83) states and as a crucial test of current ideas on c c dynamics. Estimates are given for the rates, and possible background are also discussed.

(1978). doi:10.1016/0370-2693(78)90742-6, 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 .