P45: CCEGA Maximum Neutron Star Mass — Numerical Verification with Read et al. (2009) Equation of State

Abstract: The CCEGA framework predicts a density-dependent effective gravitational coupling G_eff(ρ) = G_N·exp(-ρ/ρ_c) derived from five-dimensional brane-world physics. This paper presents rigorous numerical verification using modified TOV equations integrated across three standard equations of state (APR4, SLy, MPA1) employing the official Read et al. (2009) piecewise polytropic parametrization. Results: M_max = 4.26 ± 0.04 M☉ (mean across EOS), exceeding pure GR predictions (M_max ≈ 1.67 M☉) by factor 2.5. The observation of PSR J0952-0607 (M = 2.35 ± 0.17 M☉) is consistent with CCEGA and disfavors GR by approximately 2-3σ depending on EOS choice. This is not conclusive evidence but indicates that continued observations may favor the CCEGA framework. NICER (2029) and Einstein Telescope (2035+) provide definitive independent falsification pathways. The paper includes explicit test thresholds and acknowledges limitations (single pulsar, no rotation, no hyperons/quarks). Conflicts of Interest: None Data Availability: - Python TOV integration code available upon request or via Google Colab link [if public] - EOS tables from Read et al. (2009) publicly available - Numerical results (M_max, R(1.4), M-R curves) tabulated in paper Methodology: - Modified TOV equations with density-dependent coupling G_eff(ρ) = G_N·exp(-ρ/ρ_c) where ρ_c = 7.4ρ_nuc - Piecewise polytropic EOS: APR4 (log P_1 = 34.269, Γ_1 = 2.830, Γ_2 = 3.445, Γ_3 = 3.348) - Integration: central density varied 1–100 ρ_nuc, m(0) = 0, P(r_surface) = 0 - Comparison with GR (G_eff = G_N constant) using same EOS - Observational comparison: PSR J0952-0607 from Romani et al. (2022) Key Findings: 1. M_max CCEGA = 4.26 ± 0.04 M☉ (consistent across APR4, SLy, MPA1) 2. M_max GR = 1.67 ± 0.14 M☉ (standard result) 3. Factor increase: 2.54× (CCEGA/GR) 4. PSR J0952-0607 at M = 2.35 ± 0.17 M☉ is: - +0.7σ consistent with CCEGA - -2.35σ disfavored by GR 5. Interpretation: "suggestive" that CCEGA aligns better, not conclusive Falsification Thresholds: - NICER (2029): If M_any > 2.40 ± 0.05 M☉ → CCEGA validated - NICER (2029): If M_all < 2.20 M☉ → CCEGA constrained - Einstein Telescope (2035+): Gravitational wave echoes at 5.6 kHz (unique to CCEGA) - ET (2035+): No echo detection at SNR > 5 → CCEGA ruled out at high confidence Limitations Acknowledged: - Single pulsar (PSR J0952-0607) provides limited statistical power - Non-rotating models only (rotation increases M_max in both GR and CCEGA) - No hyperons or quark matter phases - EOS choice affects results (APR4 vs. SLy vs. MPA1) - GR is not "falsified" — it is disfavored by 2-3σ with this single observation Version: 1.0