Precision measurement of the K S meson lifetime with the KLOE detector

Using a large sample of pure, slow, short lived K 0 mesons collected with KLOE detector at DAΦNE, we have measured the K S lifetime. From a fit to the proper time distribution we find τ ( K S )=(89.562±0.029 stat ±0.043 syst ) ps. This is the most precise measurement to date of the short lived K 0 meson lifetime, in good agreement with the world average derived from previous measurements. We observe no dependence of the lifetime on the direction of the K S in galactic coordinates.