Search for the Pair Production of Dark Particles $X$ with $K_L^0\to XX$, $X\to \gamma \gamma$

Abstract

We present the first search for the pair production of dark particles $X$ via $K_L^0\to XX$ with $X$ decaying into two photons using the data collected by the KOTO experiment. No signal was observed in the mass range of 40 - 110 MeV/c${}^2$ and 210 - 240 MeV/c${}^2$. This sets upper limits on the branching fractions as $\mathcal{B}(K_L^0\to XX)$ $<$ (1-4) $\times$ 10${}^{-7}$ and $\mathcal{B}(K_L^0\to XX)$ $<$ (1-2) $\times$ 10${}^{-6}$ at the 90% confidence level for the two mass regions, respectively.

References in corpus (5)

• Pair production of dark particles in meson decays
• Long-lived neutral-kaon flux measurement for the KOTO experiment
• Development of a low-mass and high-efficiency charged particle detector
• An aerogel Cherenkov detector for multi-GeV photon detection with low sensitivity to neutrons
• Photon-Veto Counters at the Outer Edge of the Endcap Calorimeter for the KOTO Experiment

Cited by in corpus (2)

• Workshop summary -- Kaons@CERN 2023
• Sweeping the pion chimney for axion-like particles with KOTO