Upgrade of the Cesium Iodide Calorimeter for the KOTO Experiment

Abstract

The KOTO experiment, conducted at J-PARC (Ibaraki Japan), is set to observe the rare decay KL → πνν̄. The branching ratio is heavily suppressed in the Standard model (SM) and the experimental observation may reveal hints from physics beyond the SM. The observed signature ofKL → πνν̄ is two γ’s produced from a π and no other signal. Thus the KOTO detector consists of an electromagnetic calorimeter and hermetic veto counters.