Triton to proton magnetic moment ratio

$μₜ/μₚ$ = 1.066 639 9189(21)

Value: 1.066 639 9189
Standard uncertainty: 2.1 × 10⁻⁹
Relative uncertainty: 2.0 × 10⁻⁹ (2 parts per billion)
Status: Measured
Symbol: $μₜ/μₚ$
Source: CODATA 2022 via NIST · NIST entry

Use in a calculation

# triton to proton magnetic moment ratio, CODATA 2022 (NIST)
triton_to_proton_magnetic_moment_ratio = 1.0666399189  # standard uncertainty 2.1e-9

# SciPy: scipy.constants.physical_constants['triton to proton mag. mom. ratio']

What it is

The magnetic moment of the triton divided by the magnetic moment of the proton. Ratios like this are often measured more precisely than either quantity on its own, which is why CODATA lists them.

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	1.066 639 9189(21)	2.0 × 10⁻⁹	−0.1 σ of 2018
2018	1.066 639 9191(21)	2.0 × 10⁻⁹	+1.1 σ of 2006
2006	1.066 639 908(10)	9.4 × 10⁻⁹

“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).