Mabuchi solitons and Mabuchi constants on Fano admissible manifolds

In this paper, we study the existence of Mabuchi solitons on admissible manifolds as defined by Apostolov–Calderbank–Gauduchon–Tønnesen-Friedman. We prove that a Fano admissible manifold admits a Mabuchi soliton if and only if the Mabuchi constant is less than 1. We also provide an explicit formula for the Mabuchi constant on Fano admissible manifolds, which generalizes that of Mabuchi. Using this formula, we completely determine the existence and non-existence of Mabuchi solitons on Fano admissible manifolds over the complex projective space ${\mathbf{P}}^n$.