NA48 is an experiment from elementary particle physics, in which the physics is examined by kaons. Particular attention is paid to the CP violation. The experiment is located in the North Area of the CERN Super Proton Synchrotron at. From the structure of the experiments NA48 -1 went, NA48 -2 and also called NA62 NA48 -3 produced.
In 1999 it was possible to NA48, as well as at KTeV to confirm the evidence for direct CP violation in the NA31 experiment.
The first stage of NA48 -1 went in 2002 with minimally altered structure in operation and sought primarily by very rare KS decays. But even some hyperon and less rare K -decays were studied.
NA48 -2, in turn, had set itself the aim of investigating a possible high statistics decays of charged kaons. The data collection took place in the years 2003 to 2004.
The third expansion NA48 -3, which is now under NA62, is the rare decay
Investigate. The experiment is currently in the construction phase and in 2014 to begin data acquisition.
Operation and Results
In NA48 the cross ratio was measured.
It denote the various decay amplitudes of the two CP eigenstates ( durable ) and ( short-lived ).
This ratio can be used to measure the relationship of the direct CP violation.
KL beam was, like the CS - beam generating means 450 GeV protons auftrafen on a target. The KL- target stood 200 m in front of the detector, the KS target 100 m. The distinction between the KL and KS decays was carried out over a 10-10 s on accurate measurement of the flight time and the possible thereby determining the place of origin.
The charged pions were detected in the experiment in four drift chambers, which were erected in pairs behind and in front of a dipole magnet. The uncharged pions were detected via their decay into photons in a krypton - tank, which was divided into 13,212 cells of size 2 x 2 cm2.
The result of the experiment is