Measurement of the charge asymmetry for the $K_S\to \ddot{I}€e\hat{I}½$ decay and test of CPT symmetry with the KLOE detector

Abstract

Using 1.63 fb${}^{-1}$ of integrated luminosity collected by the KLOE experiment about $7\times 10^4$ $K_S\to \ddot{I}{€}^{\pm }{e}^{\mp }\hat{I}½$ decays have been reconstructed. The measured value of the charge asymmetry for this decay is $A_S=(-4.9\pm 5.7_{stat}\pm 2.6_{syst})\times 10^{-3}$, which is almost twice more precise than the previous KLOE result. The combination of these two measurements gives $A_S=(-3.8\pm 5.0_{stat}\pm 2.6_{syst})\times 10^{-3}$ and, together with the asymmetry of the $K_L$ semileptonic decay, provides significant tests of the CPT symmetry. The obtained results are in agreement with CPT invariance.

submitted to JHEP