First results from phi -> KL KS decays with the KLOE detector
  The KLOE experiment has collected 2.4 1/pb of integrated luminosity during the commissioning of the DAFNE phi-factory in 1999. The performance of the detector has been studied using phi -> KL KS decays collected during this period, yielding also first measurements of relevant K parameters such as masses and lifetimes. A clean Kshort -> pi+ pi- sample is used to select Klong -> 2pi CP-violating decays and Klong -> Kshort regeneration events in the detector material. Results on the regeneration probability in beryllium-alluminum alloy and carbon-fiber plus aluminum composite are presented. 
The KLOE Collaboration