New light weakly coupled sectors can help resolve many outstanding issues in particle physics, such as the nature of dark matter. Such "hidden sector" particles can be produced at fixed-target experiments, including neutrino facilities based around proton beamlines such as Booster and NuMI at Fermilab. The new particles produced at Booster and NuMI could leave signatures inside the liquid argon detectors of the Short-Baseline Neutrino program, whose mm-level spatial and ns-level temporal resolution will be able to help reject backgrounds, including those from neutrino scattering. I will review the physics of hidden sectors and describe the Short-Baseline Neutrino program at Fermilab. Then, I will discuss a potential search for a specific hidden sector model known as the Higgs portal, consisting of a new light scalar which mixes with the Higgs boson. We expect that for scalar masses of order 100 MeV, the Fermilab detectors will be able to probe the Higgs portal at mixing angles up to an order of magnitude smaller than existing limits.
