Phenomenology of CP-even ALP

Axion or axion-like particle (ALP) has been usually considered as a CP-odd Nambu-Goldstone boson (NGB) from the spontaneous breakdown of global U(1) symmetry. In this paper, we point out that NGB behaves CP-even coupled to SM particles in large class simple (or perhaps simplest) renormalizable models. We provide first study collider phenomenology and cosmology ALP. natural parameter region, ALP can be produced Higgs decay colliders. When mass is not very light, signals will exotic decays, displaced vertex $\times 2$, + missing energy. The signal discriminated other models, e.g. hidden photon, by measuring length products light new particle. addition, when $ m_a\lesssim \,$MeV, which case invisible may probed colliders, nice Dark matter (DM) candidate. DM 21cm line measurement, future measurement Milky way halo function Vera Rubin Observatory, well X- $\gamma$-ray observations. production mechanisms are discussed.