ConstantID

Triton-proton mass ratio

Atomic & nuclearMeasured

mt/mp = 2.993 717 034 03(10)

Value
2.993 717 034 03
Standard uncertainty
1 × 10−10
Relative uncertainty
3.3 × 10−11 (33 parts per trillion)
Status
Measured
Symbol
mt/mp
Source
CODATA 2022 via NIST · NIST entry

Use in a calculation

# triton-proton mass ratio, CODATA 2022 (NIST)
triton_proton_mass_ratio = 2.99371703403  # standard uncertainty 1e-10

# SciPy: scipy.constants.physical_constants['triton-proton mass ratio']

What it is

The mass of the triton divided by the mass 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).

triton-proton mass ratio: CODATA values 1998–2022 relative to the 2022 value, in parts per trillion, with one-standard-uncertainty bars−2000−10000+1000+2000parts per trillion1998200220062010201420182022

Relative uncertainty

triton-proton mass ratio: relative standard uncertainty in each CODATA adjustment, logarithmic scale10⁻¹¹10⁻¹⁰10⁻⁹1998200220062010201420182022
CODATAValue (uncertainty)Relative uncertaintyChange from previous
20222.993 717 034 03(10)3.3 × 10−11 −0.7 σ of 2018
20182.993 717 034 14(15)5.0 × 10−11 +3.0 σ of 2014
20142.993 717 033 48(22)7.3 × 10−11 +1.1 σ of 2010
20102.993 717 0308(25)8.4 × 10−10 −0.0 σ of 2006
20062.993 717 0309(25)8.4 × 10−10

“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 mt/me Triton-electron mass ratio 5496.921 535 51(21) Atomic & nuclear gt Triton g factor 5.957 924 930(12) Atomic & nuclear μt Triton magnetic moment 1.504 609 5178(30) × 10−26 J T−1 Atomic & nuclear μt/μB Triton magnetic moment to Bohr magneton ratio 1.622 393 6648(32) × 10−3 Atomic & nuclear μt/μN Triton magnetic moment to nuclear magneton ratio 2.978 962 4650(59) Atomic & nuclear mt Triton mass 5.007 356 7512(16) × 10−27 kg Atomic & nuclear mtc2 Triton mass energy equivalent 4.500 387 8119(14) × 10−10 J Atomic & nuclear mtc2 Triton mass energy equivalent in MeV 2808.921 136 68(88) MeV