$K^{0} \leftrightharpoons \overline{K}^0$ transitions monitored by strong interactions: a new determination of the $K_{L} - K_{S}$ mass difference

The CPLEAR set-up (modified) has been used to determine the K/sub L/- K/sub S/ mass difference by a method where neutral-kaon strangeness oscillations are monitored through kaon strong interactions, rather than semileptonic decays, thus requiring no assumptions on CPT invariance for the decay amplitudes. The result, Delta m= (0.5343+or-0.0063/sub stat/+or-0.0025/sub syst/)*10/sup 10/ h(cross) /s, provides a valuable input for CPT tests. (22 refs).