CPLEAR experiment

However, baryogenesis is only possible under the following conditions proposed by Andrei Sakharov in 1967: The first experimental test of CP violation came in 1964 with the Fitch-Cronin experiment.

The experiment involved particles called neutral K-mesons, which fortuitously have the properties needed to test CP.

[4] The CPLEAR detector was able to determine the locations, the momenta and the charges of the tracks at the production of the neutral kaon and at its decay, thus visualizing the complete event.

Time-reversal invariance would imply that all details of one of the transformations could be deducible from the other one, i.e. the probability for a kaon to oscillate into an anti-kaon would be equal to the one for the reverse process.

[3] The neutral kaons are initially produced in the annihilation channels which happen when the 106 anti-protons per second beam coming from the LEAR facility is stopped by a highly-pressurized hydrogen gas target.

The low momentum of the antiprotons and the high pressure allowed to keep the size of the stopping region small in the detector.

It was compounded by a Cherenkov detector, which carried out the kaon-pion separation; and scintillators, measuring the energy loss and the time of flight of the charged particles.

The detection of photons produced in π0 decays was performed by ECAL, an outermost lead/gas sampling calorimeter, complementary to the PID by separating pions and electrons at higher momenta.