  Axion-like particles (ALPs) interacting with the Standard Model can be
abundantly produced in proton beam fixed-target experiments. Looking for their
displaced decays is therefore an effective search strategy for ALPs with a mass
in the MeV to GeV range. Focusing on the benchmark models where the ALP
interacts dominantly with photons or gluons, we show that the proposed
DarkQuest experiment at Fermilab will be able to test parameter space which has
been previously inaccessible. We pay particular attention to the
self-consistency of gluon-coupled ALP production and decay calculations, which
has been recently shown to be a problem in many existing predictions. We also
apply these results to explore existing constraints in the ALP parameter space.
