Theoretical predictions and new experimental data on 4He measured with great accuracy diverge
At the Mainz particle accelerator MAMI, the A1 collaboration has systematically measured the excitation of an α-particle, the nucleus of a 4He atom, from its ground state to the first excited state in a new way and with unprecedented accuracy as part of Dr. Simon Kegel's PhD thesis. The comparison of experiment and current calculations from the associated low-energy theory shows that the excitation of α-particles is not correctly described based on the current understanding of nuclear forces - and thus raises many questions. The scientific article was published as a recommendation of the editors in the renowned journal Physical Review Letters.