ECTI-P vs ΛCDM — Full Likelihood (CLASS + Cobaya) FAIR Comparison with Planck 2018, Pantheon+, DESI BAO, RSD, and KiDS-1000

Update v1.1:- Added modified CLASS implementation (classy_ecti_bgonly)This dataset contains the full-likelihood (CLASS + Cobaya) results for a FAIR comparison between ΛCDM and the ECTI-P model. Key results (MAP):- Δχ² = −15.69 (ECTI − ΛCDM)- H₀: 70.91 vs 67.94 km/s/Mpc- S₈: 0.812 vs 0.829 ECTI-P is a late-time, background-only deformation of ΛCDM, designed to modify the expansion history at low redshift (z ≲ 0.5) while preserving early-time physics and CMB constraints. The improvement in χ² is primarily driven by Type Ia supernovae, with additional contribution from weak lensing, while BAO and RSD remain statistically consistent and the CMB likelihood is not degraded. The model is implemented as a hybrid extension:- Modified background expansion (ECTI-P)- Standard ΛCDM perturbation sector This release includes MCMC chains, covariance matrices, configuration files, and logs used to produce the reported results. For full details and figures, see the associated GitHub repository:https://github.com/f-patellis/ECTI-P_CLASS_fullprobe_vs_LCDM版本更新至v1.1：新增改进版CLASS实现（classy_ecti_bgonly） 本数据集包含用于Λ冷暗物质（ΛCDM）与ECTI-P模型公平对比的全似然（CLASS + Cobaya）计算结果。 关键结果（最大后验估计，MAP）： Δχ² = −15.69（ECTI-P 减 ΛCDM） 哈勃常数（H₀）：70.91 与 67.94 km/s/Mpc S₈：0.812 与 0.829 ECTI-P是Λ冷暗物质模型的晚期仅背景演化修正形式，旨在修改低红移（z ≲ 0.5）阶段的宇宙膨胀历史，同时保留早期宇宙物理规律与宇宙微波背景（CMB）约束条件。 卡方值的改善主要源于Ia型超新星（Type Ia supernovae）数据，辅以弱引力透镜（weak lensing）的额外贡献；而重子声学振荡（BAO）与红移空间畸变（RSD）的结果仍保持统计一致性，且宇宙微波背景似然值未出现劣化。 该模型以混合拓展形式实现：修正的背景膨胀演化（ECTI-P）与标准Λ冷暗物质的微扰物理部分。 本次发布包含用于生成上述结果的马尔可夫链蒙特卡洛（MCMC）链、协方差矩阵、配置文件与运行日志。 如需获取完整细节与图表，请访问关联的GitHub仓库：https://github.com/f-patellis/ECTI-P_CLASS_fullprobe_vs_LCDM