The Odyssey of Kaonic Atoms Studies at the DA\(\Phi \)NE Collider: From DEAR to SIDDHARTA-2
Abstract
In this paper, an overview of kaonic atoms studies from the late 90s to nowadays at the DA$\Phi$NE collider at INFN-LNF is presented. Experiments on kaonic atoms are an important tool to test and optimize phenomenological models on the low-energy strong interaction. Since its construction, the DA$\Phi$NE collider has represented an ideal machine to perform kaonic atoms measurements, thanks to the unique beam of kaons coming from the $\phi$s produced in the collider decays. The DEAR and SIDDHARTA experiments achieved the precise evaluation of the shift and width of the 2p $\to$ 1s transition in kaonic hydrogen due to the strong interaction, and thus provided a measurement strictly linked to isospin-dependent antikaon–nucleon scattering lengths. To fully disentangle the iso-scalar and iso-vector scattering lengths, the measurement of kaonic deuterium is necessary as well. The SIDDHARTA-2 experiment is now taking data at the DA$\Phi$NE collider with the aim to fulfill the need of this measurement, and therefore provide important information to the various phenomenological models on low-energy strong interactions with strangeness. The SIDDHARTA-2 Collaboration is also exploring the possibility to perform future kaonic atoms experiments, developing X‑ray detector systems beyond the current state-of-art. These measurements are crucial for a deeper understanding of the kaon interactions with nuclei and for solving the kaon mass "puzzle".