The proton size

JP Karr, D Marchand, E Voutier - Nature Reviews Physics, 2020 - nature.com
The proton charge radius has been measured since the 1950s using elastic electron–proton
scattering and ordinary hydrogen atomic spectroscopy. In 2010, a highly precise …

Proton-electron mass ratio from laser spectroscopy of HD+ at the part-per-trillion level

S Patra, M Germann, JP Karr, M Haidar, L Hilico… - Science, 2020 - science.org
Recent mass measurements of light atomic nuclei in Penning traps have indicated possible
inconsistencies in closely related physical constants such as the proton-electron and …

Precise test of quantum electrodynamics and determination of fundamental constants with HD+ ions

S Alighanbari, GS Giri, FL Constantin, VI Korobov… - Nature, 2020 - nature.com
Bound three-body quantum systems are important for fundamental physics, because they
enable tests of quantum electrodynamics theory and provide access to the fundamental …

Proton–electron mass ratio by high-resolution optical spectroscopy of ion ensembles in the resolved-carrier regime

IV Kortunov, S Alighanbari, MG Hansen, GS Giri… - Nature physics, 2021 - nature.com
Optical spectroscopy in the gas phase is a key tool for elucidating the structure of atoms and
molecules and their interaction with external fields. The line resolution is usually limited by a …

Penning trap mass measurements of the deuteron and the HD+ molecular ion

S Rau, F Heiße, F Köhler-Langes, S Sasidharan… - Nature, 2020 - nature.com
The masses of the lightest atomic nuclei and the electron mass are interlinked, and their
values affect observables in atomic, molecular,–and neutrino physics, as well as metrology …

Benchmarking Theory with an Improved Measurement of the Ionization and Dissociation Energies of

N Hölsch, M Beyer, EJ Salumbides, KSE Eikema… - Physical review …, 2019 - APS
The dissociation energy of H 2 represents a benchmark quantity to test the accuracy of first-
principles calculations. We present a new measurement of the energy interval between the …

Three-body QED test and fifth-force constraint from vibrations and rotations of

M Germann, S Patra, JP Karr, L Hilico, VI Korobov… - Physical Review …, 2021 - APS
We present a parts-per-million test of quantum electrodynamics (QED) in the HD+ molecular
hydrogen ion, improving on previous tests based on vibrational and rotational transitions by …

Mass difference of tritium and helium-3

M Medina Restrepo, EG Myers - Physical Review Letters, 2023 - APS
From cyclotron frequency ratios of HD+/He+ 3, HD+/T+, and T+/He+ 3 we measure the mass
difference between atoms of T and He 3 to be 1.995 940 8 (23)× 10-5 u, corresponding to a …

Laser spectroscopy of a rovibrational transition in the molecular hydrogen ion

MR Schenkel, S Alighanbari, S Schiller - Nature Physics, 2024 - nature.com
Abstract Comparison of precise predictions of the energy levels of the molecular hydrogen
ion H 2+—the simplest molecule—with measured vibrational transition frequencies would …

Nonadiabatic QED correction to the dissociation energy of the hydrogen molecule

M Puchalski, J Komasa, P Czachorowski, K Pachucki - Physical Review Letters, 2019 - APS
The quantum electrodynamic correction to the energy of the hydrogen molecule has been
evaluated without expansion in the electron-proton mass ratio. The obtained results …