A USP Field Theory Interpretation of the Cosmic Microwave Background: Δf-Decay, Resonance Floors, and Photon Fate

The Cosmic Microwave Background (CMB) is derived in USP Field Theory as the universal resonance floor produced by Δf-decay. All photon corridors eventually lose coherence and collapse into the minimum resonant frequency: Δf_min = k_B T / h ≈ 56 GHz CMB blackbody peak ≈ 160 GHz (statistical population maximum) USP interprets Δf_min as the deterministic “endpoint of light,” while the peak frequency emerges from the distribution of excited modes above this minimum. The document harmonizes with: msf:47650 (Δf corridor decay geometry) msf:47300 (survival filtering and Δf_crit) msf:45740 (time as Δf rhythm) The result is a clean, non-singular explanation of the CMB as the final state of photon resonance, independent of Big Bang requirements.