Canonical analysis of the fermion sector in higher-derivative supergravity

The degree of freedom and helicity count of the fermionic sector in generic superconformal plus supergravity models is exhibited by explicit elimination of all constraints in the 3+1 decomposition of the action, which is given entirely in terms of gauge-invariant variables. In the purely superconformal, massless, case, the third-derivative action describes three helicity-$\frac{3}{2}$ excitations and one of helicity ½. When mass is introduced by adding a Rarita-Schwinger term, a new helicity-½ excitation appears, and the total spectrum now consists of two massive spin-$\frac{3}{2}$ modes plus a massless one. In both cases, the excitations unavoidably emerge in sets with both signs of the Hilbert-space metric; some implications of this ghost behavior are discussed.