[en] We have measured the K-series x-rays of kaonic hydrogen atoms to determine the strong-interaction energy-level shift and width of the 1s atomic state with significant improvements over the previous experiments. The measurement offers a unique possibility to precisely determine the complex K^-p S-wave scattering length. We have also measured kaonic x-ray spectra with several gaseous targets : deuterium, helium-3 and helium-4. In this paper, we present an overview of this experiment and preliminary spectra of those kaonic x-rays.

[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] 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] The KN system at rest makes a sensitive testing ground for low energy QCD. At the DAΦNE electron-positron collider of Laboratori Nazionali di Frascati we study kaonic atoms, taking advantage of the low-energy kaons from Φ-mesons decaying nearly at rest. The DEAR (DAΦNE Exotic Atom Research) experiment at LNF delivered the most precise data on kaonic hydrogen up to now. DEAR and its follow-up experiment SIDDHARTA (Silicon Drift Detector for Hadronic Atom Research by Timing Application) are using X-ray spectroscopy of kaonic atoms to measure the strong interaction induced shift and width of the ground state. SIDDHARTA is the first experiment on kaonic helium-3 and deuterium ever, and kaonic hydrogen was remeasured with improved precision.

[en] The VIP (Violation of the Pauli Exclusion Principle) experiment is dedicated to check the validity of one of the basic principles of modern physics. This investigation is done searching for anomalous X-rays emitted by copper atoms in a conductor: any detection of these anomalous X-rays would mark a Pauli forbidden transition. VIP is currently taking data at the Gran Saso underground laboratories, and its scientific goal is to improve by three-four orders of magnitude the previous limit on the probability of Pauli violating transitions, bringing it into the 10^-29 to ^-30 region. The new experimental results and future plans are presented. The PDF file for this article was corrected and the names and affiliations were amended on 4 September 2009.

[en] The Pauli exclusion principle (PEP) represents one of the basic principles of the modern physics. Even if there are no compelling reasons to doubt its validity, it still spurs a lively debate, because an intuitive, elementary explanation is still missing, and because of its unique stand among the basic symmetries of physics. A new limit on the probability that PEP is violated by electrons was established by the VIP (VIolation of the Pauli exclusion principle) Collaboration, using the method of searching for PEP forbidden atomic transitions in copper. The preliminary value, 1/2 β² <6 x 10^-29, represents an improvement of more than two orders of magnitude of the previous limit. The goal of VIP is to push this limit at the level of 10^-30.

[en] The Pauli exclusion principle (PEP), consequence of the spin-statistics connection, is one of the basic principles of the modern physics. Being at the very basis of our understanding of matter, as many other fundamental principles it spurs a lively debate on its possible limits, deeply rooted in the very foundations of Quantum Field Theory. Therefore, it is extremely important to test the limits of its validity. Quon theory provides a suitable mathematical framework of possible violation of PEP, where the violation parameter q translates into a probability of violating PEP. The VIP (VIolation of the Pauli exclusion principle) experiment established a new limit on the probability that PEP is violated by electrons, using the method of searching for PEP forbidden atomic transitions in copper. We describe the experimental method, the obtained results, both in terms of the q-parameter from quon theory and as probability of PEP violation, we briefly discuss them and present future plans to go beyond the actual limit by upgrading the experimental setup. We also shortly mention the possibility of using a similar experimental technique to search for eventual X-rays, generated in the spontaneous collapse models in quantum mechanics.

[en] The Pauli Principle represents one of the most important rules in physics and explains numerous phenomena as well as characteristic properties of matter, like its stability. Testing the validity of this principle at the highest possible sensitivity is a challenging experimental task - the VIP experiment at the Gran Sasso underground laboratory aims at a limit for the violation probability of the order of 10^-29 to 10^-30. The method is based on the search for Pauli-forbidden x-ray transitions in a pure copper conductor using silicon x-ray detectors with high resolution in energy. The experimental setup, results obtained so far and new ideas to further enhance the sensitivity will be presented.

[en] One of the fundamental rules of nature and a pillar in the foundation of quantum theory and thus of modern physics is represented by the Pauli Exclusion Principle. We know that this principle is extremely well fulfilled due to many observations. Numerous experiments were performed to search for tiny violation of this rule in various systems. The experiment VIP at the Gran Sasso underground laboratory is searching for possible small violations of the Pauli Exclusion Principle for electrons leading to forbidden X-ray transitions in copper atoms. VIP is aiming at a test of the Pauli Exclusion Principle for electrons with high accuracy, down to the level of 10⁻²⁹ – 10⁻³⁰, thus improving the previous limit by 3–4 orders of magnitude. The experimental method, results obtained so far and new developments within VIP2 (follow-up experiment at Gran Sasso, in preparation) to further increase the precision by 2 orders of magnitude will be presented

[en] One of the fundamental rules of nature and a pillar in the foundation of quantum theory and thus of modern physics is represented by the Pauli Exclusion Principle. We know that this principle is extremely well fulfilled due to many observations like the order of the elements and the stability of matter. Numerous experiments were performed to search for tiny violation of this rule in various systems. The VIP experiment at Gran Sasso underground laboratory is testing the validity of this principle for electrons with very high precision (order of 10^-30). The layout of the present experiment, results obtained so far and new ideas to further increase the precision will be presented.