The SIDDHARTA-2 experiment for high-precision kaonic-atoms X-ray spectroscopy.

The study of kaonic atoms plays a key role for the understanding of the low-energy quantum chromodynamics (QCD) in the strangeness sector, by allowing to directly access the antikaon-nucleus interaction at threshold. State-of-the-art X-ray detectors and suitable experimental technologies allow to perform kaonic-atoms X-ray spectroscopy with unprecedented precision, providing fundamental results for the nuclear, particle and astrophysics research. To this end, the SIDDHARTA-2 experiment at INFN-LNF DAFNE collider is carrying on its data taking campaign, aiming at performing high-precision X-ray spectroscopy of kaonic atoms, in particular the first measurement of kaonic-deuterium X-ray transition to the fundamental level to completely solve the isospin-dependent antikaon-nucleon scattering length. The scientific case and the SIDDHARTA-2 experiment will be presented.