0000000000248332
AUTHOR
C. Ebersberger
First measurement of the rate K0L → πμνγ
Abstract In a preliminary version of the NA48 experiment at the CERN SPS, in which an iron-scintillator sandwich calorimeter was used as a photon detector, the ratio of K L → πμνγ and K L → πμν decays was measured. The branching ratio BR(K L →πμνγ, E γ ∗ ≥30 MeV )/(K L → πμν ) is found to be (2.08±0.17 +0.16 −0.21 )×10 −3 , where the first error is statistical and the second systematic. The result is in agreement with theoretical predictions.
The tagging detector of the CP-violation experiment NA48 at CERN
Abstract The CP-violation experiment NA48 at CERN aims at measuring direct CP-violation in the decays of neutral kaons into π + π − and π 0 π 0 . The experiment uses simultaneous, almost collinear beams of neutral K L 0 and K S 0 mesons, which are produced on two different targets. K S 0 events are “tagged” by measuring the times of the protons that fly towards the K S 0 production target. In order to sustain the high rate of 10 7 protons/s in this beam without suffering from too many pile-up events, the detector consists of 24 separate scintillators (12 horizontal and 12 vertical), each of which sees only a small fraction of the beam. Their signals are digitized by specially developed 1 G…
Measurement of the decay rate and form factor parameter in the decay KL→e+e−γ
Abstract The decay rate of the neutral K meson KL→e+e−γ 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(KL→all) = (1.06±0.02stat±0.02sys±0.04calc)×10−5. The parameter α K ∗ describing the relative strength of the two contributing amplitudes to this decay through intermediate pseudoscalar or vector mesons was measured to be α K ∗ =−0.36±0.06stat±0.02sys.
The tagging detector of the NA48 experiment
First test results are reported from the NA48 K s tagging system. The system consists of two subdetectors. One samples the passing time of each proton which will hit the K s target ( tagging detector ), the other one measures the event time of a charged Kaon decay ( hodoscope for charged decays ). The tagging detector was read out with a FADC system operating with a sampling frequency of 480MHz. A time resolution of 182ps and resolving of double pulses down to 4ns could be achieved.