Positivity and Microcausality in Scalar–Vector–Spinor Effective Field Theory

A five-dimensional scalar–vector–spinor effective field theory (SVS-EFT) requires a physical state space and a causal kinetic operator in addition to its Clifford-algebraic organization. We construct a one-time compact benchmark that makes these requirements explicit and separates them from a proposed projection in the real algebra . The proposed map fails idempotency, whereas the spacelike compact operator with a unitary twist yields a positive, stable four-dimensional spectrum. For two probes separated by half the circumference, we derive an exact normalized transfer identity that factorizes the holonomy and geometric attenuation. Antiperiodicity cancels the entire cross-response without removing local physical states. We prove that a nonzero finite sum of ordinary particle poles cannot reproduce the exact interval before compact first arrival, although each retained mode remains four-dimensionally microcausal. A symmetry-preserving cutoff protects the interference zero; an unpaired cutoff produces a calculable false signal. We also specify the representation-dependent relation between the compact twist and a metaplectic angle, and verify the leading scalar absorptive cut. An exact scattering-space leakage identity states the additional condition required for a projected sector to close. These results give the SVS-EFT programme a concrete consistency benchmark without assuming an interacting completion.