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SYAD: Symposium SAMOP Dissertation Prize 2022
SYAD 1: SAMOP Dissertation Prize Symposium
SYAD 1.4: Invited Talk
Tuesday, March 15, 2022, 15:30–16:00, Audimax
Precision Mass Measurement of the Deuteron’s Atomic Mass — •Sascha Rau — Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
The rest masses of many light nuclei, e.g. the proton, deuteron, triton and helion are of great importance for testing our current understanding of physics as well as in metrology. One example are comparisons of rotational and vibrational spectra in HD+ molecular ions with theory, which can be used to test 3-body QED calculations [1]. There, the masses of the involved particles are required as input parameters. Recently discussed discrepancies in measurements of these masses, carried out at different mass spectrometers and termed light ion mass puzzle, strongly call for investigation through independent measurements.
In my talk, I will present a mass measurement of the deuteron’s atomic mass [2] carried out at LIONTRAP, a high-precision spectrometer dedicated to light ions. There, a newly implemented superconducting magnetic field-shaping coil enabled overcoming the leading systematic uncertainty for light ion mass measurements. This enabled us to reach a precision of δ m/m = 8.5× 10−12, the most precise measurement in atomic mass units so far. The observed 5 σ discrepancy to the previous best measurement does not only reduce the light ion mass puzzle significantly, but is also confirmed by a series of systematic checks, including a direct measurement of the HD+ mass and comparisons with HD+ spectroscopy.
[1] M. Germann et al., Phys. Rev. Reas. 3, L022028 (2021)
[2] S. Rau et al., Nature 585, 43-47 (2020)