Status on the Search for $K_L^0 \rightarrow \pi^0 \nu \bar{\nu}$ with the KOTO Experiment

Understand

The KOTO experiment at the J-PARC research facility in Tokai, Japan aims to observe and measure the rare decay of the neutral kaon, $K_L^0 \rightarrow \pi^0 \nu \bar{\nu}$.

• This decay has a Standard Model (SM) predicted branching ratio (BR) of $(3.00 \pm 0.30) \times 10^{-11}$.
• While this decay is extremely rare, it is one of the best decays in the quark sector to probe for new physics beyond the SM due to small theoretical uncertainties.
• The E391a experiment at KEK 12-GeV PS previously searched for $K_L^0 \rightarrow \pi^0 \nu \bar{\nu}$ events and set a limit of BR($K_L^0 \rightarrow \pi^0 \nu \bar{\nu}$) $< 2.6 \times 10^{-8}$ in 2010.