Kaonic 3He and 4He measurements in the SIDDHARTA experiment at the DAΦNE collider

The SIDDHARTA collaboration measured kaonic 3He and 4He 3d → 2p X-rays with gaseous targets at the DAΦNE e+e− collider. The 2p-state strong-interaction shifts and widths were precisely determined by using 144 high-resolution silicon drift detectors. The shift of K−4He is in good agreement with theoretical calculations and consistent with the recent experimental result of KEK-PS E570. The shift of K−3He is also determined for the first time. The newly determined widths are in agreement with optical model calculations.