Towards the X-ray measurement of kaonic deuterium at J-PARC

Hashimoto, Tadashi   

X-ray spectroscopy of kaonic atoms is a unique method to probe the anti-kaon nucleon/nuclear interaction at very low energy, which is almost impossible to be done with a standard scattering experiment. Kaonic hydrogen and kaonic deuterium have special importance since we can extract iso-spin dependent anti-kaon nucleon scattering length by measuring strong-interaction-induced energy-level shift and broadening in 1s states. However, it is experimentally difficult to measure the 2p-1s transition X-rays from these atoms due to a low X-ray yield and a large natural line widt. We are preparing for an experiment at J-PARC to measure X-rays from kaonic deuterium (J-PARC E57). We will realize a good signal-to-noise ratio measurement by using high collecting efficiency silicon drift X-ray detector arrays and a cylindrical detector system to select events from the target and to reject background events caused by secondary charged particles.