Basis-independent ALP Phenomenology with and without Weak interactions

Rare neutral kaon decays provide a sensitive probe of the flavor and CP structure of axion-like particle (ALP) couplings. I will present the first calculation of the weak-interaction contribution to three-body neutral kaon decay rates and compare these with two-body decays for representative benchmarks. For heavier ALPs, I will then introduce a basis-independent framework that unifies quark and gluon couplings and enables data-driven predictions of decay rates across the transition from the hadronic to the perturbative QCD regime.