The muon collider as a H/AH/A factory

We show that a muon collider is ideally suited for the study of heavy H/AH/A scalars, cousins of the Higgs boson found in two-Higgs-doublet models and required in supersymmetric models. The key aspects of H/AH/A are: (1) they are narrow, yet have a width-to-mass ratio far larger than the expected muon collider beam-energy resolution, and (2) the larger muon Yukawa allows efficient s  -channel production. We study in detail a representative Natural Supersymmetry model which has a 1.5TeVH/AH/A with mH−mA=10GeV. The large event rates at resonant peak allow the determination of the individual H and A resonance parameters (including CP) and the decays into electroweakinos provide a wealth of information unavailable to any other present or planned collider.