Joint Standing-Carrier Closure for the Neutrino Sector

Neutrino carrier ARC and HNL prediction 14/18 This paper provides the joint standing-carrier closure for the neutrino sector by combining the target extensions developed across PCR‑5D1 through PCR‑5D5. The preceding papers extend the oscillation standing-carrier space to direct kinematic mass, lepton-number violation, heavy-state and active-sector closure, cosmological population and transport, and symmetry and charge structure. PCR‑5E brings these extensions into one jointly evaluated target rather than treating them as independent marginal tests. The analysis constructs a common joint target containing the retained oscillation interface, direct kinematic response, \(^{76}\mathrm{Ge}\) lepton-number-violating response, heavy-state and active-closure data, cosmological population and transport structure, and symmetry, charge, and conjugation coordinates. Each component retains its own source, response, applicability, covariance, matching, and failure semantics while participating in a shared physical realization. A central requirement is simultaneous joint compatibility. A candidate must possess one coherent source-faithful physical witness supporting all activated target extensions at once. Separate compatibility with individual targets is not sufficient when the corresponding structures cannot be co-instantiated, matched, transported, or made consistent with one common carrier and physical interior. The paper preserves the established standing-carrier identity discipline throughout the joint construction. Lawful redescription, basis changes, parameter charts, target projections, and extension-specific factorizations cannot merge carrier classes while retained standing separators remain defined. Conversely, target-inert decorations and source-null structures do not generate spurious carrier multiplicity. The resulting joint object records the surviving carrier classes, their joint incidence data, activated target coordinates, shared source and matching structure, compatibility relations, and typed failure or out-of-scope boundaries. The construction therefore provides a single closure surface for the neutrino sector while preserving the distinction between carrier identity, target response, physical realization, and later experimental interpretation. The principal result is a joint standing-carrier closure relative to the fixed PCR source ontology, comparison class, base SCIC quotient, and activated target extensions. It establishes which previously surviving carrier structures remain jointly admissible under the combined target bundle and exports the resulting joint residue to the subsequent analysis of the physical nature and minimal identity of the neutrino carrier. The conclusion is deliberately bounded. This paper does not by itself select a unique microscopic carrier, determine a unique mass mechanism, establish a unique Dirac or Majorana interpretation, provide a complete cosmological likelihood, or constitute experimental confirmation. Its contribution is the joint, source-faithful closure of the standing-carrier extension structure before the carrier-identity analysis of PCR‑6.