New precision era of experiments on strong interaction with strangeness at DAFNE/LNF-INFN

The strong-interaction shifts and widths of kaonic hydrogen, deuterium, He-3, and He-4 were measured in the SIDDHARTA experiment. The most precise values of the shift and width of the kaonic hydrogen is state were determined to be is an element of(1s) = -283 +/- 36(stat) +/- 6(syst) eV and Gamma(1s) = 541 +/- 89(stat) +/- 22(syst) eV. The upper limit of the kaonic deuterium K alpha yield was found to be <= 0.39%. In addition, the shifts and widths of the kaonic He-3 and He-4 2p states were determined to be is an element of(2p)(He-3) = -2 +/- 2(stat) +/- 4(syst) eV and Gamma(2p)(He-3) = 6 +/- 6(stat) +/- 7(syst) eV; is an element of(2p)(He-4) = +5 +/- 3(stat) +/- 4(syst) eV and Gamma(2p)(He-4) = 14 +/- 8(stat) +/- 5(syst) eV. These values are important for the constraints of the low-energy KN interaction in theoretical approaches.