Universal Critical Mass for Quantum Collapse ( Mc ): A Cosmological Limit to Unitarity

We propose the existence of a fundamental mass scale, Mc≈5.3×10−16, where quantum unitarity is spontaneously violated due to interaction with the cosmological acceleration horizon. Derived from a geometric constraint on the 8-dimensional phase space, Mc=mP(a0/aP)1/8 this hypothesis predicts that spatial superpositions of masses M>Mc decay into statistical mixtures within a finite intrinsic time. This provides a clear, falsifiable target for next-generation levitated optomechanics experiments.