Neutron magnetic moment to nuclear magneton ratio

$μₙ/μ_N$ = −1.913 042 76(45)

Value: −1.913 042 76
Standard uncertainty: 4.5 × 10⁻⁷
Relative uncertainty: 2.4 × 10⁻⁷ (235 parts per billion)
Status: Measured
Symbol: $μₙ/μ_N$
Source: CODATA 2022 via NIST · NIST entry

Use in a calculation

# neutron magnetic moment to nuclear magneton ratio, CODATA 2022 (NIST)
neutron_magnetic_moment_to_nuclear_magne = -1.91304276  # standard uncertainty 4.5e-7

# SciPy: scipy.constants.physical_constants['neutron mag. mom. to nuclear magneton ratio']

What it is

The magnetic moment of the neutron, the electrically neutral nucleon, expressed in nuclear magnetons.

How the value changed, 1998–2022

Each point is one CODATA adjustment, plotted as its difference from the 2022 value; the bars show one standard uncertainty (an arrowhead means the bar runs off the chart).

Relative uncertainty

CODATA	Value (uncertainty)	Relative uncertainty	Change from previous
2022	−1.913 042 76(45)	2.4 × 10⁻⁷	−0.1 σ of 2018
2018	−1.913 042 73(45)	2.4 × 10⁻⁷	+0.0 σ of 2014
2014	−1.913 042 73(45)	2.4 × 10⁻⁷	−0.0 σ of 2010
2010	−1.913 042 72(45)	2.4 × 10⁻⁷	+0.0 σ of 2006
2006	−1.913 042 73(45)	2.4 × 10⁻⁷	+0.0 σ of 2002
2002	−1.913 042 73(45)	2.4 × 10⁻⁷	−0.0 σ of 1998
1998	−1.913 042 72(45)	2.4 × 10⁻⁷

“Change from previous” is the shift in the value divided by the standard uncertainty of the previous adjustment. Earlier values are converted into the current unit where NIST changed it (for example J s to J Hz⁻¹).