Limits RegistryPUBLIC RECORD
Limits RegistryThe KATRIN experiment at the Karlsruhe Institute of Technology measured the energies of about 36 million tritium beta-decay electrons over 259 measurement days and, in Science in April 2025, set an upper limit of 0.45 eV/c^2 on the neutrino mass. That halved its own previous bound and is the best direct, cosmology-independent neutrino-mass limit.
The question, scope, and sources behind this Registry record.
The KATRIN experiment at the Karlsruhe Institute of Technology measured the energies of about 36 million tritium beta-decay electrons over 259 measurement days and, in Science in April 2025, set an upper limit of 0.45 eV/c^2 on the neutrino mass. That halved its own previous bound and is the best direct, cosmology-independent neutrino-mass limit.
The smallest model-independent (kinematic) upper bound on the effective electron-antineutrino mass obtained in a laboratory.
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Current frontiers derived from accepted Claims.
An observed or demonstrated result; no opposing bound is implied.
The frontier is not sacred
Most progress starts with a disagreement that survives contact with evidence. If you can push the known lower bound up or pull the upper bound down, show us the work.
≥ when you have shown that at least this value is achievable.≤ when you have shown that anything above this value is impossible.No vibes. State the value, define the scope, and link the paper, proof, code, or reproduction that lets another person check it. Editors review every challenge before the public record changes.
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The frontier as it changed over time.
Only accepted Claims matching the current specification contribute to the displayed bounds. Strict inequalities remain open; contradictory Claims require editorial review.
1 accepted Claim, with 1 linked evidence records.
Permanent ID limitsregistry.com/limits/LR-NEUTRINO-MASS-DIRECT-UPPER-LIMIT
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Limits Registry. LR-NEUTRINO-MASS-DIRECT-UPPER-LIMIT. Tightest direct laboratory upper limit on the neutrino mass. 2026.