GR-Razor Stress Tests-Pillar 16: Geometric Baryogenesis: The Irreversible Weyl Excitation from Zero Gravitational Entropy as the Origin of Matter-Antimatter Asymmetry

Cosmological Pangea The universe contains matter. It contains almost no antimatter. For sixty years, explaining that asymmetry has required new particles, new forces, new energy scales, and assumptions that go beyond everything we have confirmed in the laboratory. This paper requires none of those things. The Navigable Universe framework derives the thermodynamic arrow of time from a single initial condition: zero gravitational entropy at the Cosmological Pangaea epoch. The irreversible symmetry breaking that follows excites the Weyl tensor from zero, establishes the future direction of time, and, as this paper demonstrates, simultaneously satisfies all three of Sakharov's conditions for baryogenesis from pure geometry. Baryon number violation comes from electroweak sphalerons, standard model physics already in the literature. CP violation comes from the gravitational axial anomaly during Weyl excitation, with the sign of the asymmetry fixed by the direction of the thermodynamic arrow. Departure from thermal equilibrium is the breaking itself. Nothing new is introduced. The mechanism was always there, implicit in the geometry, waiting for a framework that started from zero entropy to make it explicit. The sign of the baryon asymmetry, matter over antimatter, is a prediction. It is aligned with the thermodynamic arrow by geometric necessity. A universe with an antimatter excess would require a reversed arrow, which is incompatible with the zero-entropy initial condition and the Penrose hypothesis. The sign has never been derived before. It is derived here. The quantitative amplitude eta approximately 10^-38 per topological unit falls 26 to 30 orders below the observed 6.12 x 10^-10. The gap is identified precisely as the effective topological multiplicity of independent instanton-like configurations contributing coherently to the net Pontryagin density during the breaking transition. The holographic bound and CET entropy scaling both give N_P,eff of order 10^5 per Hubble patch. The required value is 10^28. That gap is a result, not a failure. It is the first precise numerical constraint on quantum gravity at the Pangaea epoch to emerge from cosmological observation and geometric derivation combined: any complete theory of quantum gravity must produce N_P,eff approximately 10^28 per comoving Hubble volume at the breaking epoch. This paper is the first to state that number. Four independent observational channels test the sign prediction before 2035: BBN and CMB precision tightening of eta, CMB-S4 and LiteBIRD detection of arrow-aligned helical B-modes, pulsar timing array and LISA constraints on a chiral gravitational wave background, and PTOLEMY measurement of the cosmic neutrino background asymmetry. The mechanism is falsifiable. The sign is on the table. The baryon asymmetry is not a coincidence of initial conditions. It is a geometric consequence of a universe that began at zero gravitational entropy and broke that symmetry in a direction we call the future. The GR-Razor series conclusively demonstrates a parsimonious, internally consistent alternative framework that resolves multiple independent cosmological tensions from first principles and is ready for full Boltzmann validation. 1. 10.5281/zenodo.18736909 – Independent Cosmological Falsification Series. 2. 10.5281/zenodo.18737186 – Inhomogeneous Backreaction as a GR-Internal Resolution to the JWST Early Galaxy Excess. 3. 10.5281/zenodo.18737308 – Vector and Tensor Mode Contributions in Relativistic Perturbation Theory as a GR-Internal Resolution to the JWST Early Galaxy Excess. 4. 10.5281/zenodo.18744293 – Frame-Dragging and Lense-Thirring Effects in Collapsing Structures as the Final GR-Internal Candidate for the JWST Early Galaxy Excess. 5. 10.5281/zenodo.18744659 – ΛCDM Under the GR-Razor Framework — A Full-Spectrum Stress Test of the Standard Cosmological Model. 6. 10.5281/zenodo.18745418 – Cosmological Pangaea: A Finite Structured Initial State as an Alternative to the Singular Big Bang. 7. 10.5281/zenodo.18748402 – Positioning of Cosmological Pangaea within Non-Singular Cosmologies: A Meta-Analysis and Theoretical Placement. 8. 10.5281/zenodo.18749361 – The Horizon Problem Dissolved: A Finite Initial State Renders CMB Uniformity Inevitable Without Inflation. 9. 10.5281/zenodo.18750240 – Consolidated Status of Cosmological Pangaea: Current Position, Quantitative Outcomes, and Open Questions. 10. 10.5281/zenodo.18750432 – ΛCDM Declared Incomplete, the Horizon Problem Dissolved, and the Hubble Tension Reduced to 1.39σ by a First-Principles Quantum Bounce. 11. 10.5281/zenodo.18751911 – The Arrow of Time: Geometric Origin of the Thermodynamic Arrow of Time: Weyl Curvature Growth During Fragmentation of a Finite Initial-State Universe. 12. 10.5281/zenodo.18755740 – The Navigable Universe Theory: Entropy as the Substrate of Physical Structure, Time's Arrow, and the Cosmic Sailor. 13. 10.5281/zenodo.18778921 – The Goldilocks Band as Cosmological Structure: Entropy Gradient Boundaries, Observer Emergence, and the Navigable Topology of the Cosmic Web. 14. 10.5281/zenodo.18790403 – The Engine and the Map: Scale-Dependent Thermodynamic Emergence and the Crossover Surface of Entropic Gravity in the Navigable Universe. 15. 10.5281/zenodo.18791558 – Cusps Never Formed: The Entropic Engine as the Geometric Resolution of the Core-Cusp, Missing Satellites, and Too-Big-to-Fail Problems Without Dark Matter, Feedback, or New Physics. 16. 10.5281/zenodo.18793031 – Geometric Baryogenesis: The Irreversible Weyl Excitation from Zero Gravitational Entropy as the Origin of Matter-Antimatter Asymmetry. 17. 10.5281/zenodo.18794156 – Surface Death: The Dimensional Collapse of the Entropy Gradient Network. 18. 10.5281/zenodo.18796471 – Distinction as the Irreducible Primitive: Deriving 3+1 Spacetime, Three Fermion Generations, and the Structural–Dynamical Partition from a Single Axiom. 19. 10.5281/zenodo.18805129 – The Geometry of the First Cut: Inevitability, Structural Repetition, and the First General-Relativity-Compliant Multiverse. 20. https://zenodo.org/records/18827471 – The Story of How Cosmological Pangaea Unfolded. 21. https://zenodo.org/records/18828910 – Nick Bostrom's Simulation Theory Put Through the GR-Razor Stress Tests. 22. https://zenodo.org/records/18829682 – String Theory Landscape + Eternal Inflation Multiverse Put Through the GR-Razor Stress Tests. 23. https://zenodo.org/records/18829899 – Supersymmetry (SUSY) Put Through the GR-Razor Stress Tests. 24. https://zenodo.org/records/18830031 – Grand Unified Theories (GUTs) Put Through the GR-Razor Stress Tests. 25. https://zenodo.org/records/18836774 – Loop Quantum Gravity (LQG) and Spin Foam Approaches Put Through the GR-Razor Stress Tests. 26. https://zenodo.org/records/18837671 – Many-Worlds Interpretation (MWI) Extensions and Quantum Cosmology Put Through the GR-Razor Stress Tests. 27. https://zenodo.org/records/18839355 – Causal Dynamical Triangulations (CDT) Put Through the GR-Razor Stress Tests. 28. https://zenodo.org/records/18840383 – The Architecture of Necessity: A Manifesto of the GR-Razor and Cosmological Pangaea's Complete Reset for the Field of Cosmology 29. https://zenodo.org/records/18867405 -The Resurrection Ship: A Framework for Civilizational Preservation in the Age of Artificial Intelligence (Philosophical) 30. https://zenodo.org/records/18869920 - 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