CPT symmetry

…a quantitative theory establishing combined CP as a symmetry of nature. Physicists reasoned that if CP were invariant, time reversal T would have to remain so as well. But further experiments, carried out in 1964 by a team led by the American physicists James W. Cronin and Val Logsdon Fitch,…

, the CPT theorem) that when the operation of parity reversal P is joined with two others, called charge conjugation C and time reversal T, the combined operation does leave the fundamental laws unchanged.