The ALP miracle revisited

We revisit the ALP miracle scenario where the inflaton and dark matter are unified by a single axion-like particle (ALP). We first extend our previous analysis on the inflaton dynamics to identify the whole viable parameter space consistent with the CMB observation. Then, we evaluate the relic density of the ALP dark matter by incorporating uncertainties of the model-dependent couplings to the weak gauge bosons as well as the dissipation effect. The preferred ranges of the ALP mass and coupling to photons are found to be 0.01 ≲ m_ϕ ≲ 1 eV and g_{ϕ γ γ}= O(1 0 ^{− 11}) GeV⁻¹, which slightly depend on these uncertainties. Interestingly, the preferred regions are within reach of future solar axion helioscope experiments, IAXO and TASTE, and laser-based stimulated photon-photon collider experiments. We also discuss possible extensions of the ALP miracle scenario by introducing interactions of the ALP with fermions.