Measurement ofCP violation parameters and test ofCPT invariance with\(\overline {K^0 } \) and K0 at LEARand K0 at LEAR

The CPLEAR experiment at CERN studies theCP, T andCPT symmetries in the neutral-kaon system by measuring the rate asymmetries between the decays of initially pure K0 and\(\overline {K^0 } \) states. Using data taken between 1990 and mid 1994, precise measurements of |η+-|,φ +- and Δm are reported. The comparison of φ+- the superweak phase gives one of the most sensitive tests ofCPT invariance and leads to a new limit on the\(K^0 - \overline {K^0 } \) mass difference.