neutron-proton mass ratio

Document v1 · published by Koskamo · updated 2026-10-03

neutron-proton mass ratio = 1.001 378 419 46 (CODATA 2022 recommended value, NIST)

Value: 1.00137841946
Standard uncertainty: 4.0e-10 (relative 4.0 × 10⁻¹⁰)
Unit: none (dimensionless)

Source and provenance

Original source: physics.nist.gov
Published on Koskamo by: Koskamo
Citation version: Document v1
Reuse: CODATA 2022 recommended values from NIST, a work of the US government (public domain in the United States)

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Version history

Published by Koskamo2026-10-03
Version 1