Garchinger Maier-Leibnitz-Kolloquium: The Light Ion Mass Puzzle - Precision Mass Spectrometry with Penning Traps

by Dr Olesia Bezrodnova (Institut für Physik, Univ. Mainz)

Thursday Oct 23, 2025, 4:15 PM → 5:15 PM Europe/Berlin

Lecture hall, ground floor (west) (LMU building, Am Coulombwall 1, campus Garching)

The masses of the lightest nuclei form a network of parameters relevant to fundamental physics. The mass difference between tritium and helium-3, for example, must be known to the highest precision to test for systematic uncertainties in experiments such as KATRIN or Project-8, which study tritium β-decay to set a limit on the electron antineutrino mass. A Penning-trap measurement involving the bound electron g-factor can improve the precision of electron mass in atomic mass units if the mass of the reference nucleus, helium-4, is known with sufficient precision.
Penning-trap mass measurements of the light nuclei have revealed notable inconsistencies between the values reported by different experiments. To  restore confidence in the literature values, the mass spectrometer LIONTRAP has measured the masses of the proton [1], deuteron, HD+ molecular ion [2] and helium-4 [3]. The final measurement of the experiment, namely the mass of helium-3 [4], provides independent, high-precision data for the last missing link between the masses in the regime of light ions, thereby resolving discrepancies among the reported values of light atomic nuclei from various experiments, known as the Light Ion Mass Puzzle.

[1] F. Heiße et al. Phys. Rev. A 100, 022518 (2019).
[2] S. Rau et al. Nature 585, 43–47 (2020).
[3] S. Sasidharan et al., Phys. Rev. Lett. 131, 093201 (2023).
[4] O. Bezrodnova et al., Phys. Rev. A 111, L040801 (2025)

Hybrid access via ZOOM:
https://lmu-munich.zoom.us/j/98457332925?pwd=TWc3V1JkSHpyOTBPQVlMelhuNnZ1dz09
Meeting ID: 984 5733 2925
Passcode: 979953

 

kolloquium-23-10-25.pdf