Penning-Trap Mass Measurement of Helium-4

Abstract

Light-Ion Trap (LIONTRAP), a high-precision Penning-trap mass spectrometer, was used to determine the atomic mass of ${}^4$He. Here, we report a 12 parts-per-trillion measurement of the mass of a ${}^4$He${}^{2+}$ ion, $m{(}^4{\text{He}}^{2+}$) = $4.001506179651(48)$ u. From this, the atomic mass of the neutral atom can be determined without loss of precision: $m{(}^4\text{He})$ = $4.002603254653(48)$ u. This result is slightly more precise than the current CODATA18 literature value but deviates by 6.6 standard deviations. This is a post-peer-review, pre-copy edit version of an article published in PRL. The final version is available online at https://doi.org/10.1103/PhysRevLett.131.093201.

6 pages, 5 figures

References in corpus (6)

• High-precision measurement of the atomic mass of the electron
• Proton-Electron Mass Ratio from Laser Spectroscopy of HD${}^{+}$ at the Part-Per-Trillion Level
• Penning-trap mass measurements of the deuteron and the HD+ molecular ion
• High-precision mass spectrometer for light ions
• A new mass value for 7Li
• $\text{Direct}Q\text{-Value Determination of the}{\beta }^{-}\text{Decay of}{}^{187}\text{Re}$