Axion-Photon Coupling in the E8-X Unified Field Theory

Abstract We compute the axion–photon coupling constant \ (g₀ \) from first principles within the \ (E₈ \) –\ (X \) Unified Field Theory. The axion emerges naturally as a pseudo-Goldstone mode from the spontaneous symmetry breaking \ (E₈ E₆ SU (3) F \), corresponding to a topological pseudo-scalar component of the fundamental field \ (X 248 \). Using the unique representation theory of compact \ (E₈ \) and the anomaly cancellation structure, we derive a parameter-free prediction ₀ 1. 24 10^-17 \, GeV^-1, \ which lies within the sensitivity reach of current and next-generation axion experiments. This result provides a sharp, falsifiable signature of the \ (E₈ \) –\ (X \) theory. ---