Successor Target for Quantitative Active Closure in the Neutrino Standing-Carrier Space

Neutrino carrier ARC and HNL prediction 11/18 This paper develops the successor-target extension of the PCR‑5D3 heavy-state analysis, introducing a quantitatively complete active-closure target for the source-qualified neutrino carrier space. PCR‑5D3 establishes a source-qualified prompt-heavy-neutral-lepton continuum together with structural heavy support, active-sector closure, and charged-lepton-flavour constraints. The present paper strengthens the experimental target by requiring quantitative coverage of every active primitive in the declared low-mass weak-universality response, rather than allowing qualitative compatibility or incomplete applicability to stand in for a complete test. The successor target is constructed independently of candidate outcomes and inherits the fixed PCR‑5B standing-carrier quotient, PCR‑5C target-extension calculus, PCR‑4 survivor relations, and PCR‑5D3 source-qualified heavy-state domain. Its response structure includes the active-sector closure relation, low-mass lepton-flavour-universality data, charged-current support, heavy-state matching, source and restriction maps, applicability guards, covariance information, and target-relative acceptance conditions. A source-first prompt-HNL family is then evaluated over the declared mass and response domain. The analysis preserves the distinction between source-qualified structural support, detector response, quantitative target coverage, physical pole data, and experimental sensitivity. A surviving prompt-HNL continuum remains in the restriction image of the enriched target, while the standing-carrier base structure is preserved. The paper also constructs an exact source-indexed atlas over the declared finite-operational scope. The atlas records actual source indices, applicability, quantitative response status, failure provenance, target-relative restriction, and the distinction between evaluated points and responses that are out of scope. Finite algebraic and RCF-based evaluation is used as an execution surface for the declared operational fragment; it is not presented as unrestricted physical or ultraviolet exhaustion. The principal result is that quantitative active closure can be imposed as a genuine successor target without silently selecting a unique carrier or collapsing the prompt-HNL family to a single realization. The surviving continuum demonstrates that improved quantitative coverage strengthens the experimental authority of the target while preserving source-level multiplicity where the theorem chain continues to license it. The analysis explicitly retains unresolved non-RCF and out-of-scope remnants rather than treating them as eliminated. A response classified as outside the declared operational domain remains a live target-relative boundary or update condition, not an automatic failure of the underlying carrier. The conclusion is deliberately bounded. The paper establishes successor-target closure and quantitative active-closure analysis within the declared source, response, and finite-operational scope. It does not establish an unrestricted global atlas, a unique heavy-neutrino microscopic origin, an exact physical pole mass or lifetime, present-facility discovery sensitivity, or a unique neutrino carrier.