neutron-proton mass difference

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

neutron-proton mass difference = 2.305 574 61 × 10⁻³⁰ kg (CODATA 2022 recommended value, NIST)

Value: 2.30557461e-30
Standard uncertainty: 6.7e-37 (relative 2.9 × 10⁻⁷)
Unit: kg

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