A Phenomenological Model of Gravitational Decoherence: The Entropion χ as a Neutral Residual Mass Parameter

We introduce a phenomenological extension of gravitational decoherence models in the spirit of Diósi–Penrose, in which the residual mass associated with a fully decohered electron is parametrized by a dimensionless degree °M. This residual mass, termed the entropion χ, is defined through a phenomenological mass correspondence p + e⁻ → n + χ; this relation should not be interpreted as a new fundamental interaction or dynamical process, but rather as a limiting correspondence of masses in the fully decohered regime. The entropion carries neither electric charge nor electromagnetic coupling. The mass relation m_χ = m_e (1 - °M/90°) is applied to two reference systems: AR 11158 (°M = 45°) and the hypothetical compact object BH3 (°M = 89.1°). Three quantitative, falsifiable predictions are derived: (i) absence of residual infrared emission from BH3, (ii) violation of the weak equivalence principle at the level ∼10⁻¹³, and (iii) an explicit dependence of the effective gravitational acceleration on the residual coherence factor (S/U)⁻¹. A concrete laboratory test using presolar SiC grains is proposed. The framework is consistent with existing decoherence theory (Zurek) while remaining open to experimental refutation.