Direct search for light gluinos

We present the results for a direct search for light gluinos through the appearance of eta --> 3 pi0 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^-3 s and another one between 10^-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~ bound state, the R0 hadron, and its R0 --> eta gamma~ decay in the R0 mass range between 1 and 5 GeV

Measurement of the decay rate and form factor parameter alpha(K)* in the decay KL -> e+ e- gamma

The decay rate of the neutral K meson K_L --> 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 Gamma(K_L --> e+ e- gamma)/ Gamma(K_L --> all) = (1.06 +- 0.02 stat +- 0.02 sys +- 0.04 calc) * 10^-5. The parameter alphaK* describing the relative strength of the two contributing amplitudes to this decay through intermediate pseudoscalar or vector mesons was measured to be alphaK* = (-0.36 +- 0.06 stat +- 0.02 sys)

Determination of the relative decay rate KS -> pi e nu / KL -> pi e nu

The decay rate of KS > pi e nu relative to the rate of KL > pi e nu has been measured by the NA48 collaboration in a neutral Kaon beam originating from 400 GeV proton-Be interactions at the CERN SPS. The result is 0.993±0.026stat±0.022syst, compatible with 1 in agreement with the Standard Model prediction