The DEAR Case

The scientific program and the experimental setup of the DEAR (DAFNE Exotic Atom Research) experiment at the new ϕ-factory DAFNE of Laboratori Nazionali di Frascati, are described. The objective of DEAR is to perform a 1% measurement of the K_α line shift due to the strong interaction in kaonic hydrogen. A measurement will also be performed on kaonic deuterium for the first time. The aim is to investigate low-energy KN physics and to understand SU(3) chiral symmetry breaking. The setup takes advantage of the unique features of the "kaon beam" from the f decay in DAFNE; of a low-temperature pressurized gaseous target; and of a detector for soft X rays- the Charge-Coupled Device (CCD) - characterized by a good resolution and by an unprecedented background rejection capability. The DEAR experiment represents a major effort in the study of low energy KN interactions and has the potential to produce a breakthrough in the field.