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 (10)

• High-precision measurement of the atomic mass of the electron
• Measurement of the Electron Magnetic Moment
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Cited by in corpus (2)

• Improved Measurements of Muonic Helium Ground-State Hyperfine Structure at a Near-Zero Magnetic Field
• Sympathetic cooling of charged particles in Penning traps using electron cyclotron radiation