Search for a violation of the Pauli exclusion principle for atomic electrons and for nucleons

Abstract The Pauli exclusion principle would be violated if three atomic electrons would occupy the atomic K shell or if three protons or three neutrons would be in the nuclear 1 s 1 2 shell. Accelerator mass spectrometry at the Munich accelerator laboratory was used to look for such non-Paulian atoms of 20 Ne and 36 Ar and for non-Paulian nuclei of 5 Li with three protons in the nuclear 1s 1 2 shell. A time-of-flight technique was used for the identification of non-Paulian 20 Ne and 5 Li . In the case of Ar, post-accelerated hydrogen-like ions were looked for. The following limits were obtained: [ 20 Ne ] [ 20 Ne ] −21 , [ 36 Ar ] [ 36 Ar ] −17 and [ 5 Li ] [ Li ] −14 for binding energies of 5 Li between 0 and 40 MeV.