Kaon-nucleon strong interaction in kaonic atoms

The SIDDHARTA experiment (SIlicon Drift Detector for Hadronic Atom Research by Timing Application) aims to perform a precise measurement of the X-ray K-series of kaonic hydrogen and the first-ever measurement of kaonic deuterium, to obtain the strong-interaction energy-level shifts and widths of the lowest lying atomic states. The measurements will allow the determination of the isospin-dependent kaon-nucleon (KN) scattering lengths, directly connected to the physics of the KN interaction. The experiment uses the low-energy kaon beam generated at DAΦNE collider, high-density cryogenic targets and fast, large area X-ray spectroscopic detectors. In addition to the kaonic hydrogen and kaonic deuterium, the collaboration performed measurements of the kaonic Helium transitions to the 2p level (L-lines). Kaonic Helium 4 was measured for the first time in a gaseous target while the kaonic Helium 3 was mesured for the first time ever.