Belle II observation prospects for axionlike particle production from B meson annihilation decay

We investigate a new production mechanism of axionlike particle (ALP) from B meson annihilation decays and its observation potential at the Belle and Belle II experiments. This mechanism allows for the production of ALP from B meson decays in association with a large variety of mesons. In this article, we first estimate the branching ratios of such processes with a perturbative QCD method. Focusing on the most promising B - ha' (h = K +/-;pi +/-; D0 and Ds) channels, we perform sensitivity studies for a' decaying invisibly or into diphoton with Belle and Belle II experiments.