Overlap-Suppressed Freeze-In Dark Matter: Stability–Abundance Correlation and Geometric Constraints

This preprint presents a minimal effective-field-theory realization of overlap-suppressed freeze-in dark matter. In the framework studied here, the same geometric overlap factor controls both freeze-in production and mediator decay, so relic-abundance targeting and cosmological lifetime requirements become correlated rather than independent. This produces a finite viable overlap window and a corresponding geometric separation band for localized internal wavefunctions. The analysis is fully analytic and uses standard decay-dominated freeze-in expressions together with conservative regime-consistency checks. The resulting stability-abundance mapping remains qualitatively stable under mediator-spin changes and profile variations up to order-one factors, with only logarithmic sensitivity in the inferred geometric separation.