Testing discrete symmetries with neutral kaons at KLOE-2

Abstract

The KLOE-2 experiment at the INFN Laboratori Nazionali di Frascati has successfully concluded its data-taking at the DA$\Phi$NE collider collecting an integrated luminosity of 5.5 fb$^{-1}$ at the $\phi$ resonance peak. Together with the data sample collected by its predecessor KLOE, the total integrated luminosity of 8 fb$^{-1}$ represents the largest existing data sample in the world collected at an $e^+e^-$ collider at the $\phi$ meson peak, corresponding to $\sim 2.4 \times 10^{10}$ $\phi$-mesons produced. The entanglement in the neutral kaon pairs produced at the DA$\Phi$NE $\phi$-factory is a unique tool to test discrete symmetries and quantum coherence at the utmost sensitivity, in particular strongly motivating the experimental searches of possible CPT violating effects, which would unambiguously signal New Physics. The lepton charge asymmetry measured in $K_S$ semileptonic decays with $1.63$ fb$^{-1}$ of KLOE data, improving the statistical uncertainty of the present result by about a factor two, is reported, together with the tests of Time reversal and CPT symmetries in neutral kaon transition processes, and the search for the CP violating $K_S \rightarrow 3\pi^0$ decay with the newly acquired KLOE-2 data.