Reconciling Laboratory and Cosmological Neutrino Mass Limits via Bayesian Hierarchical Modeling

This project aims to systematically collect, evaluate, and synthesize all available laboratory and cosmological measurements related to the absolute neutrino mass scale over the period 2006–2026. Laboratory constraints include direct kinematic measurements from beta‑decay experiments such as KATRIN and its predecessors, while cosmological constraints include CMB, BAO, LSS, and combined ΛCDM-based analyses from major surveys such as Planck, ACT, and SPT. The review follows a structured and transparent methodology, including predefined inclusion and exclusion criteria, a comprehensive multi-database search strategy, and standardized data extraction procedures. A meta-analytic framework will be used to quantify central estimates and uncertainties from each class of measurements. To reconcile the known statistical tension between laboratory and cosmological constraints, the project employs a Bayesian hierarchical modeling approach. This framework allows the integration of heterogeneous datasets, explicit modeling of systematic uncertainties, and estimation of a unified posterior distribution for the absolute neutrino mass scale. The analysis will also evaluate the degree of tension between datasets and explore how different modeling assumptions affect the inferred mass limits. The final output of this project will include a PRISMA‑compliant systematic review, a meta-analysis of all eligible studies, and a Bayesian hierarchical synthesis that provides updated and jointly constrained limits on the absolute neutrino mass. All data, code, and models will be made openly available to support transparency and reproducibility.