Theoreticians zoom in on mysterious double neutron decay

Theoretical physicists have taken a new step in understanding the so-called neutrinoless double-beta decay. This decay in atomic nuclei has never been seen before, but an observation would be an important signal that the standard particle theory is not satisfactory. Theoretician Jordy de Vries of the University of Amsterdam and Nikhef is publishing with colleagues a follow-up to a paper that caused a stir in 2018. In it, they showed that existing nuclear physics calculations on an extremely rare decay overlooked an important effect. Experiments looking for that decay were using the wrong model, was the message. De Vries: 'At the time we could indicate that the calculations were wrong, but not how much. Our new paper provides an answer to that, too, with which the real nuclear physicists can get to work.' The new paper, which can be read on Arxiv, has now been accepted by the journal Physical Review Letters.