The SGCU 47 MeV Neutral Scalar Boson: Prediction, Properties, and Experimental Verification

The SGCU (Cosmic Topology) theory predicts a neutral scalar boson of mass m_φ ≈ 47 MeV/c², the φ resonance, identified as the ground-state quantum of normal vibration of spatial layers with geometric label $(N=3, L=1, W=0, C=0, Q=0)$. This paper systematically presents the complete physical properties of this particle: basic attributes, coupling strengths, decay characteristics, production cross-sections, experimental signatures, and unique discriminants. Three exclusive experimental fingerprints are emphasized: an extremely narrow resonance peak (intrinsic width ~ keV), scalar nature (spin 0, parity +), and an inverted leptonic coupling hierarchy (gφ ee > gφ μμ > gφ ττ). A comprehensive assessment of existing experimental constraints identifies the Belle II e⁺e⁻ initial-state radiation channel as the current optimal search window. The parameter space has not yet been excluded; the only tension lies in the precise value of g_τ / gₑ. This paper provides a concrete experimental verification proposal suitable for direct submission to the Belle II and BESIII collaborations.