Helion mass energy equivalent in MeV
Atomic & nuclearMeasured
= 2808.391 611 12(88) MeV
- Value
- 2808.391 611 12 MeV
- Standard uncertainty
- 8.8 × 10−7 MeV
- Relative uncertainty
- 3.1 × 10−10 (313 parts per trillion)
- Status
- Measured
- Symbol
- Source
- CODATA 2022 via NIST · NIST entry
Use in a calculation
# helion mass energy equivalent in MeV, CODATA 2022 (NIST)
helion_mass_energy_equivalent_in_mev = 2.80839161112e3 # MeV, standard uncertainty 8.8e-7
# SciPy: scipy.constants.physical_constants['helion mass energy equivalent in MeV']What it is
The rest energy (mass × c²) of the helion, the nucleus of helium-3 (two protons and one neutron), in mega-electronvolts, the unit particle physicists use.
In other units
| Unit | Value | |
|---|---|---|
| CGS (cm2 g s−2) | 0.004 499 539 418 46 | |
| keV kiloelectronvolt | 2 808 391.611 12 | |
| GeV gigaelectronvolt | 2.808 391 611 12 | |
| erg erg | 0.004 499 539 418 46 |
Converted with ConstantID's unit table; digits are rounded to the precision of the value, and a long exact value is rounded only for display. The relative uncertainty is unchanged by conversion to an exactly defined unit.
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 | 2808.391 611 12(88) | 3.1 × 10−10 | +4.3 σ of 2018 |
| 2018 | 2808.391 607 43(85) | 3.0 × 10−10 | +1.3 σ of 2014 |
| 2014 | 2808.391 586(17) | 6.1 × 10−9 | +1.7 σ of 2010 |
| 2010 | 2808.391 482(62) | 2.2 × 10−8 | +1.4 σ of 2006 |
| 2006 | 2808.391 383(70) | 2.5 × 10−8 | −0.2 σ of 2002 |
| 2002 | 2808.391 42(24) | 8.5 × 10−8 | +0.9 σ of 1998 |
| 1998 | 2808.391 32(11) | 3.9 × 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).