Measurement of charge asymmetry for the ${{\rm{K}}}_{{\rm{S}}}\to \pi ev$ decay and test of CPT symmetry with the KLOE detector

Using 1.63 fb−1 of integrated luminosity collected by the KLOE experiment about decays have been reconstructed. The measured value of the charge asymmetry for this decay is AS = (−4.9 ± 5.7stat ± 2.6syst) x 10−3 which is almost twice more precise than the previous KLOE result. The combination of these two measurements gives AS = (−3.8 ± 5.0stat ±2.6syst) x 10−3 and, together with the asymmetry of the KL semileptonic decay, provides significant tests of the CPT symmetry. The obtained results are in agreement with CPT invariance.