Shielded helion magnetic moment to Bohr magneton ratio

$μₕ′/μ_B$ = −1.158 671 494 57(94) × 10⁻³

Value: −1.158 671 494 57 × 10⁻³
Standard uncertainty: 9.4 × 10⁻¹³
Relative uncertainty: 8.1 × 10⁻¹⁰ (811 parts per trillion)
Status: Measured
Symbol: $μₕ′/μ_B$
Source: CODATA 2022 via NIST · NIST entry

Use in a calculation

# shielded helion magnetic moment to Bohr magneton ratio, CODATA 2022 (NIST)
shielded_helion_magnetic_moment_to_bohr_ = -1.15867149457e-3  # standard uncertainty 9.4e-13

# SciPy: scipy.constants.physical_constants['shielded helion mag. mom. to Bohr magneton ratio']

What it is

The magnetic moment of a helion in a helium-3 gas atom (spherical sample at 25 °C), screened by the atom's two electrons, expressed in Bohr 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	−1.158 671 494 57(94) × 10⁻³	8.1 × 10⁻¹⁰	−1.7 σ of 2018
2018	−1.158 671 471(14) × 10⁻³	1.2 × 10⁻⁸	+0.0 σ of 2014
2014	−1.158 671 471(14) × 10⁻³	1.2 × 10⁻⁸	+0.0 σ of 2010
2010	−1.158 671 471(14) × 10⁻³	1.2 × 10⁻⁸	+0.0 σ of 2006
2006	−1.158 671 471(14) × 10⁻³	1.2 × 10⁻⁸	+0.2 σ of 2002
2002	−1.158 671 474(14) × 10⁻³	1.2 × 10⁻⁸	+0.0 σ of 1998
1998	−1.158 671 474(14) × 10⁻³	1.2 × 10⁻⁸

“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).