ICHEP 2024

The search for KL→π0νν― in the KOTO experiment

18 Jul 2024, 09:00

15m

South Hall 1B

Parallel session talk 05. Quark and Lepton Flavour Physics Quark and Lepton Flavour Physics

Speaker

Joseph Redeker

Description

The KOTO experiment at J-PARC searches for the rare decay, $K_L\to {\pi }^0\nu \bar{\nu }$. The mode is CP-violating, with a theoretical branching ratio highly suppressed in the Standard Model at $(2.94\pm 0.15)\times {10}^{-11}$. With a small theoretical uncertainty, this search is sensitive to new physics. In the analysis of 2016-2018 data, there were three observed events within the signal region, consistent with the background estimation. An upper limit on the branching ratio was set at < $4.8\times {10}^{-9}$ (90% CL). Since that analysis, new hardware and analysis methods have been implemented to reduce the background level. The search in 2021 had a single event sensitivity of $8.66\times {10}^{-10}$ which was comparable to 2016-2018 data taking. There were no events observed in the signal region, allowing KOTO to set the best upper limit on $BR(K_L\to {\pi }^0\nu \bar{\nu })$ to date at $<1.99\times {10}^{-9}$ (90% CL). I will report on the latest result of the $K_L\to {\pi }^0\nu \bar{\nu }$ search from data taken in 2021.

Presentation materials

JRedeker_ICHEP_2024_KLpi0nunu.pdf