1.
Phys Rev Lett
; 130(11): 111801, 2023 Mar 17.
Artigo
em Inglês
| MEDLINE
| ID: mdl-37001070
RESUMO
We present the first search for the pair production of dark particles X via K_{L}^{0}âXX 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 B(K_{L}^{0}âXX)<(1-4)×10^{-7} and B(K_{L}^{0}âXX)<(1-2)×10^{-6} at the 90% confidence level for the two mass regions, respectively.