Search for the Standard Model Higgs and Z Boson decays to $J/\psi\,\gamma$: HL-LHC projections

The expected sensitivity for the measurement of Higgs and Z boson decays to $J/\psi\,\gamma$ is estimated for an integrated luminosity up to 3000 fb$^{-1}$ of $pp$ collisions at $\sqrt{s}$ = 14 TeV with an upgraded ATLAS detector at the high-luminosity LHC. For an assumed dataset of 3000 fb$^{-1}$, 95% CL upper-limits on the production of Higgs and Z boson decaying to $J/\psi\,\gamma$ of about 15 and 4 times the Standard Model expectation are obtained, respectively.