The Marie Skłodowska-Curie Action “AxiTools” investigated hypothetical particles called axions, gaining new theoretical insights and developing open-source software tools in the process. Axions are fundamental particles – somewhat similar to the Higgs boson, which was discovered in 2012 – and may explain current mysteries of the Universe, such as the origin of dark matter or why neutrons are close to perfectly “round”.
The Action contributed to the growing efforts to prove the axion’s existence in experimental searches. For instance, by studying axion models within constraints set by cosmological considerations, a new catalogue of possible models was produced, which can provide targets for future experiments. Should axions be detected, the catalogue may also allow the study of the axion’s fundamental properties and move Physics one puzzle piece closer to a “theory of everything”. Moreover, concrete experimental strategies were put forward to prove that axions are indeed the main constituent of the dark matter in the Universe.
While these are fundamental and fascinating insights, there are also more practical applications for axions beyond theoretical curiosity. The Action provides one such use case: it was demonstrated that axions could infer the solar temperature profile, i.e. measure the temperature across the Sun’s interior. The enclosed graphic shows that the temperature values inferred from a strong axion detection (black dots and bars) would closely match the underlying solar model (orange line). While the central temperature of the Sun is already known from neutrino detectors, the possibility of deducing the temperature at different points inside the Sun would be a unique advantage of axions as probes of physical systems.
Apart from illuminating the theoretical and practical role of axions, the Action’s open-science approach also contributed new software codes and datasets that can help other scientists to study and, hopefully, one day detect axions.
