Galaxy and cluster observations reveal much larger scatter and systematic deviations from the ΛCDM concentration-mass relation than predicted (Bullock & Boylan-Kolchin 2017; Kaplinghat 2016). Many dwarfs show cores where cusps are expected; some massive clusters are surprisingly over-concentrated. The diversity problem suggests halo structure is not governed solely by gravity + mass-accretion history but depends on unknown factors that break NFW universality.
The standard model has a tight c-M relation from gravity-only structure formation in cuspy NFW halos. Observed diversity at fixed mass demands either feedback prescriptions tuned per system, modified DM particle physics (warm DM, self-interacting DM), or breaking of NFW universality. None is parsimonious within minimal ΛCDM.
SCT replaces the hot-dense-center with a superluminal collision and the thermalized debris field. From this single change, halo concentration diversity is a cascade-stream + gravitational-superposition signature. Collision-seeded structure (P22, P25) deposits halos with diverse cascade-stream geometries, naturally producing a wide range of effective concentrations at fixed mass without needing fine-tuned feedback.
Gravitational superposition (P50, P51, P52, P54) gives environment-dependent Φ_mesh contribution: cluster halos sit closer to A* = 5.970 (full virialization in dense cosmic-web environments), void-region halos have lower A from less coherent Φ_mesh, and intermediate environments show intermediate concentrations. Angular-momentum inheritance (P31, P32) affects J/J_circ ratios that determine internal halo dynamics, contributing additional concentration diversity.
Pre-existing matter (P25) gives baryonic-content scatter at fixed total mass that further modulates the apparent concentration. The combined cascade-stream + environmental + J-inheritance + baryonic effects naturally produce the observed diversity. The same M6 framework that resolves the rotation-curve diversity (recid 112), the SHMR (recid 115), the peak-statistics deficit (recid 71), and the broader no-DM-particle phenomenology accounts for halo concentration diversity. There is no need to invoke modified DM physics or feedback fine-tuning.
If precision Euclid + LSST + Roman c-M relation surveys with environment stratification find concentration diversity uncorrelated with environment + cascade-stream J at the 5% level (purely random scatter around the ΛCDM c-M relation), the M6 cascade-stream + environmental explanation is refuted. The signature SCT prediction is concentration scaling with environment density + cascade-stream geometry indicators.