[en] The SIDDHARTA experiment at the DAΦNE collider of LNF-INFN performed in 2009 high precision measurements of kaonic hydrogen and kaonic helium atomic transitions. To determine the K-bar N isospin dependent scattering lenghts an important measurement, namely the kaonic deuterium one, is, however, still missing. Due to the very low expected yield of the kaonic deuterium K_α transition, a major improvement in the signal over background ratio is needed. To achieve a further background reduction, a second level trigger, based on the detection of charged pions produced by the K⁻ absorption on various materials, including the target gas nuclei, is planned to be implemented in the future SIDDHARTA-2 experiment. For shielding-related geometrical limitations, a single side of the scintillators can be accessed; in order to reach a good time resolution and uniform efficiency, a both-end readout was then realized with complex multi-reflection light guides. In this work, the results of the tests made on a detector prototype, performed on the πM−1 beamline of the Paul Scherrer Institute (Switzerland), are presented. The tests had the goal to determine the efficiency and the time resolution for pions, which should comply with the minimum required values of 90% and 1 ns (FWHM) respectively. The obtained results, 96% efficiency and 750 ps FWHM for 170 MeV/c momentum pions, qualify the prototype as an excellent second level trigger for the SIDDHARTA-2 experiment. Similar results for 170 MeV/c momentum muons and electrons are also presented

[en] We will measure the X-rays from kaonic ³He 3d → 2p transition with a precision below 2 eV. It can provide crucial information on the kaon-nucleus strong interaction. The experiment (J-PARC E17) will be performed as Day-1, which is one of the first experiments in the J-PARC hadron facility in the year 2011. An overview and the present status of the J-PARC E17 experiment are described.

[en] We will measure the x-rays from kaonic ³He and ⁴He 3d→2p transition by using silicon drift detectors. Our precision goal is set to 1 eV to provide crucial information on the kaon-nucleus strong interaction in the low energy limit. The experiment is to be performed as one of the first experiment in the J-PARC hadron facility (J-PARC E17). An overview and the present status of the experiment are presented.

[en] At the DAFNE collider of LN Frascati we are using the slow kaons to investigate the K-nucleon interaction at rest in hydrogen and deuterium. We are using X-ray spectroscopy of kaonic atoms to measure the strong interaction induced shift and width of the ground state. From these the scattering lengths can be determined, which are essential for the understanding of chiral symmetry breaking in the strangeness sector. Within the project new X-ray detectors were developed: an array of large area silicon drift detectors (SDDs) having excellent energy resolution and good timing which results in a drastic suppression of background. With this technique the measurement of kaonic deuterium X-rays will be feasible for the first time.

[en] The DAΦNE electron-positron collider at the Laboratori Nazionali di Frascati of INFN has made available a unique quality low-energy negative kaons ^beam^. The SIDDHARTA experiment used this beam to perform unprecedented precision measurements on kaonic atoms, while the AMADEUS experiment plans to perform in the coming years precision measurements on kaon-nuclei interactions at low-energies, in particular to study the kaonic nuclei. The two experiments are briefly presented in this paper. (author)

[en] SIDDHARTA collaboration performed the highest precision measurement of the shift and width of the kaonic hydrogen 1s state induced by the strong interaction at the DAΦNE collider of Laboratori Nazionali di Frascati. The result provides vital constraints on the theoretical description of the low-energy K¯N interactions. (author)

[en] We will measure kaonic helium x-rays using transition-edge-sensor microcalorimeters, TES, in the J-PARC hadron experimental facility. To demonstrate the feasibility of the experiment, we performed a measurement of pionic carbon x-rays at PSI, where an excellent FWHM energy resolution of 7 eV at 6.4 keV was achieved. We also evaluated the expected TES performance in the kaon beam at J-PARC. The simulation results show that the TES spectrometer would work with a good energy resolution, and clear peaks of kaonic helium x-rays would be observed on a reasonably suppressed background. (author)

[en] The DAΦNE electron-positron collider at the Frascati National Laboratory of INFN (Italy) has made available a unique quality low-energy negatively charged kaons 'beam', which is used to unveil the secrets of the kaon-nucleon/nuclei interactions at low energies through the SIDDHARTA-2 and AMADEUS experiments. SIDDHARTA has already performed unprecedented precision measurements of kaonic atoms, and is being presently upgraded, as SIDDHARTA-2, to approach new frontiers. SIDDHARTA-2 will measure the kaonic deuterium transitions to the 1s level. The AMADEUS experiment will perform the first complete study of the low-energy kaon-nuclei interactions by using a series of cryogenic gaseous targets as d, "3He, "4He, and solid targets. Among the aims of AMADEUS are: the measurement of the Λ(1405) decaying to Σ π in all possible combinations and to give a definite answer to the debated question of the existence of the kaonic nuclei. If such states exist we will measure their properties (binding energies, width and decay channels)

[en] The SIDDHARTA experiment measured X-rays from kaonic helium atoms using, for the first time, gaseous ³He and ⁴He targets. Clear patterns of the L-series X-rays of kaonic ³He and ⁴He atoms were observed. By using accurate Monte Carlo simulations, the absolute yields of these X-ray transitions were determined to be Y(3d → 2p) = 25.0_-5.8^+6.7 % for ³He (0.96 g/l), Y(3d → 2p) = 23.1_-4.2^+6.0 % for ⁴He (1.65 g/l), and Y(3d → 2p) = 17.2_-9.5^+2.6 % for ⁴He (2.15g/l). In addition, the yields Y (nd → 2p), with n > 3 were also determined. The measured yields provide valuable information for understanding the cascade processes of kaonic helium atoms as a function of the target density. (orig.)

[en] We have measured K-series kaonic hydrogen X-rays in the SIDDHARTA experiment performed at the DAΦNE electron-positron collider of Laboratori Nazionali di Frascati. As the kaon source, we use the low momentum and almost monochromatic kaons from the φ(1020) → K"+K"- decay at the interaction point (IP) of DAΦNE. The kaons that eventually enter the target are identified by the coincidence of two scintillators close to the IP. With a gaseous hydrogen target of density 15 ρ(STP), preliminary values of the absolute yields, defined as the number of atomic X-rays emitted per kaon stopped inside the target, were determined to be 0.012+0.003-0.004 for K_α transition and 0.045+0.009-0.012 for K_t_o_t, the summation of all the emitted K-series transitions