First thought on a high-intensity KS experiment

The K → µµ decays have recently been identified as another golden kaon physics mode along-side the rare K→πνν¯ processes. These golden modes provide precision tests of the Standard Model with very high sensitivity to New Physics. The presented study is exploring the possibility to address the KL − KS → μ+μ− interference experimentally and outlines the challenges associated with such an ambitious project for the far future. A next-generation experiment at the intensity frontier is required that should be capable of collecting a large sample of ð'ª(1014 − 1015 ) KL and KS decays. Challenges related to the beamline design and detector technology need to be overcome if we want to address this mode experimentally. A significant background suppression of KS → π+π− and radiative KL → μ+μ−γ decays is imperative for a few % measurement, which would require excellent kinematic resolution and efficient photon detection. The first attempt at a possible experimental setup to measure this effect is presented. Last but not least, a huge number of neutral particles produced offers the possibility to study a plethora of other rare KL, KS decays as well as hyperon decays enhancing the physics motivation for such an initiative.