Ultra-high energy cosmic rays (UHECRs) reach energies exceeding 10²⁰ eV. The GZK cutoff implies they must originate from local extragalactic sources within ~50-200 Mpc, but no known local sources can both accelerate particles to these energies and account for the observed flux + composition + isotropy (Alves Batista 2019; Aab 2020). The standard model lacks sufficient candidate sources with the required acceleration efficiencies.
The standard model expects UHECRs to come from known extreme-environment sources (AGN jets, GRBs, starburst-galaxy-driven shocks). Reproducing the observed UHECR flux, composition (heavy nuclei dominant at highest energies), and broad isotropy across local extragalactic sky requires source populations and acceleration mechanisms beyond what standard hierarchical-galaxy + AGN populations provide.
SCT replaces the hot-dense-center with a superluminal collision and the thermalized debris field. From this single change, UHECR origins come from cascade-thermalized + cascade-seeded source signatures. The cascade collision energy regime (P22, P23: cascade-stage events at T_QCD ≈ 10¹² K with kinetic energies of ~10c) provides natural high-energy acceleration of heavy nuclei from the inherited cascade-thermalized plasma.
Cascade-seeded compact objects (P46) plus pre-existing extreme-environment sources from prior cycles (P25, P28) provide ongoing acceleration at the calibrated UHECR rate. The cascade-deposited heavy-nuclei budget is substantial because pre-existing matter (P25) brings in nuclei from prior nucleosynthesis cycles, providing the heavy-composition observed at the highest UHECR energies. Local Big Bang context (P26) places cascade-seeded sources distributed throughout the local extragalactic sky, giving the observed isotropy.
Multi-stage cascade dynamics (P36, P37, P38) sets the broader cosmic-web context where UHECR sources sit. Gravitational superposition (P50, P51, P52) provides the cosmic-web infrastructure that hosts these sources. The same M11 framework that resolves the FRB diversity (recid 153), the diffuse gamma-ray background (recid 157), the extragalactic radio background (recid 159), and the broader cascade-seeded compact-object phenomenology accounts for UHECR origins as cascade-seeded source signatures.
If precision Pierre Auger + Telescope Array + Cherenkov + IceCube UHECR surveys identify all UHECR sources as standard known-population AGN/GRB/starburst at the 5% level (no cascade-seeded extreme-source contribution), the M11 cascade-seeded explanation is refuted. The signature SCT prediction is UHECR sources matching the cascade-seeded compact-object population distribution across the local extragalactic sky.