Status of Searching KL →Πνν in the Koto Experiment at J-Parc
Chieh Lin1*, Yee Bob Hsiung1
1Physics, National Taiwan University, Taipei, Taiwan
* presenting author:Jay Lin,
The KOTO experiment aims to search the rare kaon decay: KL→π⁰νν, which provides us one of the best probes to test the standard model. KL→π⁰νν involves a direct CP violation process and FCNC loop, hence the branching ratio is quite small. Since the theoretical uncertainty of its branching ratio is pretty small (around 2%) in the standard model prediction, it is also sensitive to the new physics. E391a had already measured it and gave the best upper limit 2.6 10-8 on branching ratio. In 2015, the KOTO experiment collected more physics data and the number of protons on target was around 20 times larger than that in E391a. With a higher statistics and better performance of detectors, we expected to get an improved result in the future.

Keywords: KOTO, E14, J-PARC, Kaon, CP violation