  New light pseudoscalars, such as axion-like particles, appear in many
well-motivated extensions of the Standard Model and provide an exciting target
for present and future experiments. We study the experimental sensitivity for
such particles by revising the CHARM exclusion contour, updating bounds from
LHCb and presenting prospects for NA62 and SHiP. We first consider a simplified
model of a light pseudoscalar $A$ and then propose a model-independent approach
applicable to any spin-0 boson light enough to be produced in B-meson decays.
As illustration, we provide upper bounds on $\text{BR}(B \to K\,A) \times
\text{BR}(A \to \mu^+\mu^-)$ as a function of the boson lifetime and mass for
models that satisfy minimal flavour violation. Our results demonstrate the
important complementarity between different experiments resulting from their
different geometries.
