= Massless Rarita-Schwinger polarization count
{title2=$h=\pm3/2$}
Gauge equivalence $\psi_\mu\sim\psi_\mu+\partial_\mu\epsilon$ permits gamma-trace gauge. The <Rarita-Schwinger field> equation then gives transversality and a massless <Dirac equation> for each component. For momentum along the third axis, residual gauge removes the temporal and longitudinal components. The remaining constraint is $\psi_2=\gamma^1\gamma^2\psi_1$, with $\psi_1$ in the two-dimensional kernel of $\not p$. Spinor helicity $\pm1/2$ is paired with vector helicity of the same sign, leaving only $\pm3/2$. A <Majorana spinor> reality condition identifies antiparticles; a Dirac vector-spinor has separate antiparticle modes.
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