Measurement of the charge asymmetry for the KS → πeν decay and test of CPT symmetry with the KLOE detector

Anastasi, A.; Babusci, D.; Berlowski, M.; Bloise, C.; Bossi, F.; Branchini, P.; Budano, A.; Cao, B.; Capon, G.; Ceradini, F.; Ciambrone, P.; Curciarello, F.; Czerwinski, E.; D’Agostini, G.; Danè, E.; De Leo, V.; De Lucia, E.; De Santis, A.; De Simone, P.; Di Cicco, A.; Di Domenico, A.; Domenici, D.; D’Uffizi, A.; Fantini, A.; Fantini, G.; Fermani, P.; Fiore, S.; Gajos, A.; Gauzzi, P.; Giovannella, S.; Graziani, E.; Ivanov, V. L.; Johansson, T.; Kang, X.; Kisielewska-Kaminska, D.; Kozyrev, E. A.; Krzemien, W.; Kupsć, A.; Loffredo, S.; Lukin, P. A.; Mandaglio, G.; Martini, M.; Messi, R.; Miscetti, S.; Moricciani, D.; Moskal, P.; Passeri, A.; Patera, V.; Perez del Rio, E.; Raha, N.; Santangelo, P.; Schioppa, M.; Selce, A.; Silarski, M.; Sirghi, F.; Solodov, E. P.; Tortora, L.; Venanzoni, G.; Wislicki, W.; Wolke, M.

doi:10.1007/JHEP09(2018)021

Using 1.63 fb−1 of integrated luminosity collected by the KLOE experiment about 7 × 104 KS → π±e∓ν decays have been reconstructed. The measured value of the charge asymmetry for this decay is AS = (−4.9 ± 5.7stat ± 2.6syst) × 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) × 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.