Lattice determination of the neutrino background for $J/\ddot{I}ˆ\to {\hat{I}}^3+\text{invisible}$

Yu Meng, Ning Li, Chuan Liu +3

The paper presents the first lattice QCD calculation of the Standard Model decay J/ψ → γ ν ν̄, providing a branching fraction of about 1×10⁻¹⁰ to serve as a neutrino background ben…