7 research outputs found

    Direct search for light gluinos

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    We present the results for a direct search for light gluinos through the appearance of η→3π0\eta\rightarrow 3\pi^{0} with high transverse momentum in the vacuum tank of the NA48 experiment at CERN. We find one event within a lifetime range of 10−9−10−310^{-9}-10^{-3}s and another one between 10−10−10−910^{-10}-10^{-9}s. Both events are consistent with the expected background from neutrons in the beam, produced by 450 GeV protons impinging on the Be targets, which interact with the residual air in the tank. From these data we give limits on the production of the hypothetical gg~g\widetilde{g} bound state, the R0R^0 hadron, and its R0→ηγ~R^0\rightarrow\eta\widetilde{\gamma} decay in the R0R^0 mass range between 1 and 5~GeV

    Measurement of the decay rate and form factor parameter αK∗\alpha_{K^{*}} in the decay KL→e+e−γK_{L} \rightarrow e^{+}e^{-}\gamma

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    The decay rate of the neutral K meson KL→e+e−γ\mathrm{K_{L} \rightarrow e^{+}e^{-}\gamma} has been measured with the NA48 detector at the CERN SPS. A total of 6864 events has been observed with an estimated background of 10 events. The branching ratio is Γ(KL→e+e−γ)/Γ(KLrightarrowall)=(1.06±0.02stat.±0.02sys.±0.04calc.)×10−5\mathrm{\Gamma(K_{L} \rightarrow e^{+}e^{-}\gamma)/\Gamma(K_{L} rightarrow all) = (1.06 \pm 0.02_{stat.} \pm 0.02_{sys.} \pm 0.04_{calc.})\times 10^{-5}}. The parameter describing the relative strength of the two contributing amplitudes to this decay through αK∗\mathrm{\alpha_{K^{*}}} intermediate seudoscalar or vector mesons, was measured to be $\mathrm{\alpha_{K^{*}} = -0.36 \pm 0.06_{stat.} \pm 0.02_{sys.}}
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