[en] The AMADEUS experiment at the DaΦne accelerator of the Frascati National Laboratories (Italy) of INFN, will perform, for the first time, full-acceptance studies of antikaon interaction in light nuclei, with a complete experimental program for the case of the kaonic clusters. Studying the absorption of antikaon by the nucleus will provide information concerning the K-barN interaction and the modification of the kaon mass in the nuclear medium.A preliminar study of these kind of hadronic interactions is being done by the AMADEUS collaboration by analyzing the existent KLOE data.

[en] The AMADEUS experiment will perform for the first time full-acceptance studies of hadronic interactions of K^- in light nuclei, with a complete experimental program for the case of the deeply bound kaonic nuclear states. The possible formation of a kaonic cluster could provide information concerning the modification of the kaon mass and of the K(bar) N interaction in the nuclear medium a preliminary study of this kind of hadronic interaction is being done by the AMADEUS Collaboration by analyzing the KLOE data. (author)

[en] Pionium (π ⁺ π ^- bound state) lifetime is measured with improved precision with respect to earlier work, and the ππ s-wave scattering length difference between I=0 and I=2 amplitudes vertical stroke a₀-a₂ vertical stroke is determined to 5% precision. (orig.)

[en] A prototype setup of scintillating fibers with silicon photomultipliers (SiPM) readout has been built and successfully operated. The implementation of such a setup as trigger system for the AMADEUS experiment is under study. Dedicated high voltage supply modules and pre-amplification cards have been built for the SiPM detectors and the whole setup has been tested in situ installed at the DAΦNE accelerator as well as with a ⁹⁰Sr beta source. The results of these tests are presented and complemented with Monte Carlo simulation.

[en] AMADEUS is an experiment planned to be performed at the DAFNE e⁺e^- collider of the Frascati National Laboratories (Italy) of INFN, to investigate the antikaon-nuclei interaction at low energies. AMADEUS will perform, for the first time, full-acceptance studies of antikaon interaction in light nuclei, including a complete experimental program for the case of the kaonic clusters. The study of the absorption of antikaon by the nucleus will provide information concerning the K-barN interaction and the modification of the kaon mass in the nuclear medium.The experiment is being preceded by the study of the hadronic interactions of K^- in the ⁴He of the drift chamber from the KLOE experiment data.

[en] Multi-Pixel Photon Counters (MPPC) consist of hundreds of micro silicon Avalanche PhotoDiodes (APD) working in Geiger mode. The high gain and the low noise, typical of these devices, together with their good performance in magnetic field, make them ideal readout detectors for scintillating fibers as trigger detectors in particle and nuclear physics experiments like AMADEUS, where such detectors are planned to be used to trigger on charged kaon pairs. In order to investigate the detection efficiency of such a system, a prototype setup consisting of 32, 1 mm diameter scintillating fibers, arranged in two double layers of 16 fibers each, and read out at both sides by 64 MPPCs with an ad-hoc built readout electronics, was tested at the πM-1 line of the Paul Scherrer Institute (PSI) in Villigen, Switzerland. The detection efficiency and the trigger capability were measured on a beam containing protons, electrons, muons and pions with a momentum of 440 MeV/c. The measured average efficiency for protons for a double layer of scintillating fibers (96.2±1.0%) represents a guarantee of the good performance of this system as a trigger for the AMADEUS experiment.

[en] Recently, the shift of the kaonic helium-4 2p state was precisely determined by the E570 and SIDDHARTA experiments. Prior to the experiment by E570, the average of three earlier experimental results showed -43±8 eV,while most of the theoretical calculations give ∼0 eV. This five-sigma discrepancy between theory and experiment was known as the 'kaonic helium puzzle'. A recent theoretical model showed a possible resonance-like shift of maximum 10 eV for a certain value of a deep antikaon-nucleon interaction potential, which is different in helium 3 and helium 4.The E570 experiment determined the shift of the kaonic helium-4 2p state as +2±2 (stat)±2 (sys) eV in 2007. The SIDDHARTA experiment determined the shift as 0±6(stat)±2(sys) eV in 2009. The results of these experiments resolved the long-standing puzzle. A new experiment of the kaonic helium-3 X-ray measurement is being prepared by the J-PARC E17 collaborators, and the kaonic helium-3 X-ray data taken very recently by the SIDDHARTA experiment are on the way to be analyzed. The results of the E570, E17 and SIDDHARTA experiments examine the strong interaction for light nuclei with different isospin, and test furthermore recent theoretical predictions.

[en] The Multi-Pixel Photon Counter (MPPC) detectors consist of hundreds of micro silicon Avalanche PhotoDiodes (APD) working in Geiger mode. The high gain and the small dimensions typical of these devices, together with their good performances in magnetic field, make them ideal readout devices for scintillating fibers as trigger detectors in particle and nuclear physics experiments like AMADEUS, where such a system is planned to be used to trigger on charged kaons. A prototype setup for this trigger system, consisting of 5 scintillating fibers readout by 10 MPPCs, was built and tested in laboratory and mounted inside the DAΦNE collider at LNF-Frascati to measure the back-to-back K⁺K⁻ pairs emitted in the Φ-decay processes. The ad hoc readout electronics was designed and realized at Laboratori Nazionali di Frascati (INFN). A 64 channels setup, with a new dedicated electronics, was then built and characterized in the laboratory. The results of the tests are presented and discussed.

[en] The planned series of measurements with AMADEUS will provide a high precision data set to study antikaon nucleus/nucleon dynamics at low energy. To achieve these goals AMADEUS will make use of the KLOE detector system at LNF, which is ideally suited for our measurements due to their large drift chamber with excellent charge particle tracking and identification probability. An almost 4π calorimeter is available for the detection of neutral particles. R and D work has already started to construct a dedicated target and trigger system for further improvements on kaon stopping efficiency and background suppression.

[en] The DEAR experiment performed at the DAΦNE electron-positron collider (Frascati, Italy) studied the strong interaction shift and width of the 1s state in kaonic hydrogen using x-ray spectroscopy. The repulsive character of the kaon-proton interaction at threshold was confirmed and the most precise values of the shift and width were obtained. However, high precision data at the percent level are highly requested to further develop the theories and thus our understanding of the low-energy antikaon-nucleon interaction. Therefore, a new series of precision experiments on kaonic hydrogen and kaonic deuterium are planned at LNF. Presented at the 20th Few-Body Conference, Pisa, Italy, 10-14 September 2007. (author)