High Precision Kaonic Atoms X-ray Spectroscopy at the DAФNE Collider: the SIDDHARTA-2 Experiment

High precision X-ray spectroscopy of light kaonic atoms provides valuable information on kaon-nucleus interaction at threshold, allowing to investigate the strong interaction in the strangeness sector at the low-energy frontier. The SIDDHARTA-2 experiment at the DA Phi NE collider of INFN-LNF is performing the challenging measurement of the kaonic deuterium 2p -> 1 s transition which together with the kaonic hydrogen measurement performed by SIDDHARTA, will allow to extract the isospin-dependent antikaon-nucleon scattering lengths. To achieve this goal, the optimization of the setup to maximize the signal over background ratio is a crucial step. This paper presents the SIDDHARTA-2 experiment and its optimization through the first observation of kaonic neon transitions. The excellent electromagnetic background reduction factor (similar to 10(4)) paves the way not only to the measurement of kaonic deuterium, but also to a new era of selected kaonic atom measurements along the periodic table.