Test of T, CP, and CPT discrete symmetries via kaons’ transitions at KLOE-2

Pairs of neutral kaons produced at the DAΦNE collider allowed to perform the first model-independent direct test of T, CP, and CPT symmetries utilizing the oscillations between the flavor and CP eigenbases. The analysis of 1.7 fb$^{-1}$ data collected in 2004–2005 in the KLOE experiment led to the determination of ratios and double ratios of kaons’ decay rates, establishing a few percent precision of the measurement in a model-free manner.