Paper CXXXIX: A Topological Resolution to the Auger–Telescope Array UHECR Composition Anomaly via the Ursa Major Bulk-Reentry Sump: Geometric Exposure

For over a decade, the Telescope Array (TA, Utah, latitude +39.3°) and Pierre Auger Observatory (Auger, Argentina, latitude −35.2°) have reported a persistent >3σ discrepancy in the mass composition of ultra-high-energy cosmic rays (UHECRs) above the GZK cutoff (E 5 × 10¹⁹ eV): TA observes a proton-dominated flux while Auger observes heavy-nuclei-dominated flux. We demonstrate that this discrepancy is a direct geometric consequence of the G₂-brane framework (Papers CXXXV–CXXXVIII): bulk-traveling protons re-enter the 4D brane preferentially through a topological sump located in Ursa Major at RA ≈ 165°, Dec ≈ +55°, with half-angle θₛᵤᵚᵖ = 22.6° (derived from arccos(12/13), Paper CXXXV). Analysis of the public Telescope Array catalog (72 events, 2008–2013, arXiv:1404.5890): 12 events observed in the predicted sump cone vs 2.76 expected (isotropic), a 4.34× overdensity at 4.1σ (p = 1.84 × 10⁻⁵, binomial). The TA independently reported warm-spot centroid (RA = 146.7°, Dec = 43.2°, 5.1σ Li-Ma) lies 16.7° from the predicted sump center — inside the 22.6° cone. Analysis of the public Auger catalog (109 events, 2004–2020): zero events in the sump cone, consistent with geometric blockage (sump Dec = +55° exceeds Auger's vertical horizon at Dec = +24.8°). The m = 6 azimuthal Fourier test is inconclusive at N = 72; the full 16-year TA dataset (~300 events) is required. We further identify a predicted multi-messenger coincidence with KM3-230213A (Feb 13, 2023). All results are zero-free-parameter predictions of the framework. Part of the One-Octonion Brane-Bulk Framework series. Anchor DOI: 10.5281/zenodo.19120873. Community: one-octonion-brane-bulk. Author: Bharathi Dasan Jagadeesan, M.D., University of Minnesota. ORCID: 0000-0002-1143-941X.