Search results for "NA48 EXPERIMENT"
showing 4 items of 14 documents
Measurement of the quadratic slope parameter in the K-L -> 3 pi(0) decay Dalitz plot
2001
A value of (-6.1 +- 0.9_{stat} +- 0.5_{syst})*10^{-3} is obtained for the quadratic slope parameter h in the K_L -> 3\pi^0 decay Dalitz plot at the NA48 experiment at the CERN SPS. The result is based on 14.7*10^6 fully reconstructed K_L -> 3\pi^0 -> 6\gamma decays. This is the most precise measurement of any of the Dalitz plot slope parameters in the charged and neutral kaon decays so far.
A measurement of the K-S lifetime
2002
A measurement of the K_S lifetime is presented using data recorded by the NA48 experiment at the CERN-SPS during 1998 and 1999. The K_S lifetime is derived from the ratio of decay time distributions in simultaneous, collinear K_S and K_L beams, giving a result which is approximately independent of the detector acceptance and with reduced systematic errors. The result obtained is tau_S=(0.89598 +- 0.00048 +- 0.00051)x10^(-10) s, where the first error is statistical and the second systematic.
A new measurement of direct CP violation in the neutral kaon system
1993
A new measurement of the ratio of the CP-violating amplitudes for $K_{L} \to 2\pi^{0}$ and $K_{L} \to \pi^{+}\pi^{-}$ is reported. The measured value for $\Re = |\eta_{00} / \eta_{ +-}|^{2}$ is $0.9878 \pm 0.0026 \pm 0.0030$, where the first error is the statistical uncertainty and the second is the estimate of the systematic uncertainty. This gives a value for the parameter describing direct CP violation: $\Re$ $\epsilon'/\epsilon = (2.0 \pm 0.7) \times 10^{−3}$ .
Observation of the decay KS→π+π−e+e−
2000
Abstract We present the first observation of the decay KS→π+π−e+e− based upon the data collected in 1998 by the NA48 experiment at CERN. We have identified a clean sample of 56 events with negligible background contamination. Using KL→π+π−π0D decays as normalization sample, the branching ratio is measured to be BR(KS→π+π−e+e−)=[4.5±0.7(stat)±0.4(syst)]×10−5. This result is in good agreement with the theoretical expectations from the mechanism of inner bremsstrahlung.