We report the first search for the KL→π0γ decay, which is forbidden by Lorentz invariance, using the data from 2016 to 2018 at the J-PARC KOTO experiment. With a single event sensitivity of (7.1±0.3stat±1.6syst)×10-8, no candidate event was observed in the signal region. The upper limit on the branching fraction was set to be 1.7×10-7 at the 90% confidence level.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)