Unified Time-Sector Effective Field Theory

Abstract We develop a time-sector effective field theory (EFT) in which time carries an internal orientation θ(x) ∈ [0, π/2) and a single positive lapse A(θ) entering a universal, time-only disformal coupling. In vacuum (θ = 0), the signal front remains luminal (under a mild UV analyticity assumption on retarded correlators), while all relativistic waves share the same leading quartic dispersion characterized by a single scale Mdisp, thereby avoiding photon-graviton speed splits. In interaction-dominated regimes (θ > 0), the same angle controls irreducible decoherence floors, general-relativity (GR)-subtracted clock residuals, and a far-observer horizon temperature rescaled by a ratio of lapses and the surface gravity. We provide an experiment-facing inference map spanning propagation, laboratory open-system platforms, clocks, and analogue horizons, and outline a cosmological extension where θ̄(t) interpolates between dark-energy-like, matter-like, and early-dark-energy-like phases. The framework is falsifiable across orthogonal channels, preserves post-Newtonian safety in vacuum, and organizes sector-universal constraints on quartic dispersion without introducing speed thresholds.