Sifting through the Standard Model for the hints of an ALP

 Considerable resources are spent for the direct detection of
exotic particles. By construction, these experiments can probe specific
regions of the parameter space of the exotics. But what if, the exotic in
question resides somewhere out of the reach of all these experiments? The
Achilles’ heel of direct detection experiments is that these are
critically dependent on the exotic mass, lifetime, and branching
fractions. In this work, we develop methods—to detect the presence of
exotics—which are largely insensitive to the mass, lifetime, and branching
fractions of the exotics. To be specific, we concentrated on the detection
of ALPs. We put forward the meson chiral Lagrangian as modified in the
presence of an ALP. We look at how processes with SM-only in-states and
out-states are modified in the presence of such a particle. This strategy
is robust in the sense that the results are largely insensitive to
unknowns like the mass of the ALP, its branching ratios, lifetime etc. In
essence, we put forward a new way to find ALPs complementary to existing
analyses.