ConstantID

Proton magnetic moment to Bohr magneton ratio

Atomic & nuclearMeasured

μp/μB = 1.521 032 202 30(45) × 10−3

Value
1.521 032 202 30 × 10−3
Standard uncertainty
4.5 × 10−13
Relative uncertainty
3.0 × 10−10 (296 parts per trillion)
Status
Measured
Symbol
μp/μB
Source
CODATA 2022 via NIST · NIST entry

Use in a calculation

# proton magnetic moment to Bohr magneton ratio, CODATA 2022 (NIST)
proton_magnetic_moment_to_bohr_magneton_ = 1.5210322023e-3  # standard uncertainty 4.5e-13

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

What it is

The magnetic moment of the proton, the nucleus of the hydrogen atom, 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).

proton magnetic moment to Bohr magneton ratio: CODATA values 1998–2022 relative to the 2022 value, in parts per billion, with one-standard-uncertainty bars−7.5−5−2.50+2.5+5+7.5parts per billion1998200220062010201420182022

Relative uncertainty

proton magnetic moment to Bohr magneton ratio: relative standard uncertainty in each CODATA adjustment, logarithmic scale10⁻¹⁰10⁻⁹10⁻⁸1998200220062010201420182022
CODATAValue (uncertainty)Relative uncertaintyChange from previous
20221.521 032 202 30(45) × 10−33.0 × 10−10 +0.0 σ of 2018
20181.521 032 202 30(46) × 10−33.0 × 10−10 −0.7 σ of 2014
20141.521 032 2053(46) × 10−33.0 × 10−9 −0.4 σ of 2010
20101.521 032 210(12) × 10−37.9 × 10−9 +0.1 σ of 2006
20061.521 032 209(12) × 10−37.9 × 10−9 +0.2 σ of 2002
20021.521 032 206(15) × 10−39.9 × 10−9 +0.2 σ of 1998
19981.521 032 203(15) × 10−39.9 × 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).

Related constants

Atomic & nuclear e/mp Proton charge to mass quotient 9.578 833 1430(30) × 107 C kg−1 Atomic & nuclear λC,p Proton Compton wavelength 1.321 409 853 60(41) × 10−15 m Atomic & nuclear mp/me Proton–electron mass ratio 1836.152 673 426(32) Atomic & nuclear gp Proton g factor 5.585 694 6893(16) Atomic & nuclear γp Proton gyromagnetic ratio 2.675 221 8708(11) × 108 s−1 T−1 Atomic & nuclear γp/2π Proton gyromagnetic ratio in MHz/T 42.577 478 461(18) MHz T−1 Atomic & nuclear μp Proton magnetic moment 1.410 606 795 45(60) × 10−26 J T−1 Atomic & nuclear μp/μN Proton magnetic moment to nuclear magneton ratio 2.792 847 344 63(82)