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The strong interaction of charged antikaons (K-) with nucleons and nuclei in the low-energy regime is a fascinating topic. The antikaon plays a peculiar role in hadron physics due to the strong attraction antikaon-nucleon which is a key question for possible kaonic nuclear bound states. A rather direct experimental access to the antikaonnucleon scattering lengths is provided by precision X-ray spectroscopy of transitions to low-lying states in light kaonic atoms like kaonic hydrogen and deuterium. After the successful completion of precision measurements on kaonic hydrogen and helium isotopes by SIDDHARTA at DAΦNE/LNF, new X-ray studies with the focus on kaonic deuterium are in preparation (SIDDHARTA2). In the future with kaonic deuterium data the antikaon-nucleon isospin-dependent scattering lengths can be extracted for the first time. An overview of the experimental results of SIDDHARTA and an outlook to future perspectives in the SIDDHARTA2 experiments in this frontier research field will be given. [ABSTRACT FROM AUTHOR]

The X-ray measurements of kaonic atoms play an important role for understanding the low-energy QCD in the strangeness sector. The SIDDHARTA experiment studied the X-ray transitions of 4 light kaonic atoms (H, D, ³He, and 4He) using the DAFNE electron-positron collider at LNF (Italy). Most precise values of the shift and width of the kaonic hydrogen 1s state were determined, which have been now used as fundamental information for the low-energy K-p interaction in theoretical studies. An upper limit of the X-ray yield of kaonic deuterium was derived, important for future K-d experiments. The shifts and widths of the kaonic ³He and 4He 2p states were obtained, confirming the end of the "kaonic helium puzzle". In this contribution also the plans for new experiments of kaonic deuterium are being presented. [ABSTRACT FROM AUTHOR]

The Pauli exclusion principle (PEP) and, more generally, the spin-statistics connection, is at the very basis of our understanding of matter and Nature. The PEP spurs, presently, a lively debate on its possible limits, deeply rooted in the very foundations of Quantum Mechanics and Quantum Field Theory. Therefore, it is extremely important to test the limits of its validity. Quon theory provides a suitable mathematical framework of possible small violation of PEP, where the q violation parameter translates into a probability of violating PEP. Experimentally, setting a bound on PEP violation means confining the q-parameter to a value very close to either 1 (for bosons) or -1 (for fermions). The VIP (VIolation of the Pauli exclusion principle) experiment established a limit on the probability that PEP is violated by electrons, using the very clean 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 and as probability of PEP violation, we briefly discuss the results and present plans to go beyond the actual limit by upgrading the experimental technique using vetoed new spectroscopical fast Silicon Drift Detectors. We discuss as well the possibility of using a similar experimental technique to search for X-rays generated as a signature of the spontaneous collapse of the wave function, predicted by continous spontaneous localization type theories. [ABSTRACT FROM AUTHOR]

The Pauli exclusion principle (PEP) is one of the basic principles of the modern physics. Being at the very basis of our understanding of matter, it spurs, presently, 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. Experimentally, setting a bound on PEP violation means confining the violation parameter to a value very close to either 1 (for bosons) or -1 (for fermions). The VIP (VIolation of the Pauli exclusion principle) experiment established a 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 technique using vetoed new spectroscopical fast Silicon Drift Detectors. We also mention the possibility of using a similar experimental technique to search for eventual X-rays, generated in the spontaneous collapse models. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The Pauli Exclusion Principle (PEP) is one of the basic principles of modern physics and, even if there are no compelling reasons to doubt its validity, it is still debated today because an intuitive, elementary explanation is still missing, and because of its unique stand among the basic symmetries of physics. We present an experimental test of the validity of the Pauli Exclusion Principle for electrons based on a straightforward idea put forward a few years ago by Ramberg and Snow (E. Ramberg and G. A. Snow 1990 Phys. Lett. B 238 438). We performed a very accurate search of X-rays from the Pauli-forbidden atomic transitions of electrons in the already filled 1S shells of copper atoms. Although the experiment has a very simple structure, it poses deep conceptual and interpretational problems. Here we describe the experimental method and recent experimental results interpreted as an upper limit for the probability to violate the Pauli Exclusion Principle. We also present future plans to upgrade the experimental apparatus. [ABSTRACT FROM AUTHOR]

The Pauli exclusion principle (PEP) is one of the basic principles of modern physics and, even if there are no compelling reasons to doubt its validity, it is still debated today 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 estabilished by the VIP (VIolation of the Pauli exclusion principle) Collaboration. The obtained value 12β2 < 4.5 × 10-28 is an improvement of about two orders of magnitude of the previous existing limit. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

The Pauli Exclusion Principle (PEP) is a basic principle of Quantum Mechanics, and its validity has never been seriously challenged. However, given its importance, it is very important to check it as thoroughly as possible. Here we describe the VIP (Violation of PEP) experiment, an improved version of the Ramberg and Snow experiment (Ramberg and Snow, Phys. Lett. B238 (1990) 438); VIP shall be performed at the Gran Sasso underground laboratories, and aims to test the Pauli Exclusion Principle for electrons with unprecedented accuracy, down to β2/2 ≈ 10-30. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

The goal of the DEAR (DAΦNE Exotic Atom Research) experiment is the precision measurement of the Kα line shift and width, due to the strong interaction, in kaonic hydrogen and the first similar measurement in kaonic deuterium. The final aim is a precision determination of the antikaon-nucleon isospin dependent scattering lengths, in order to obtain the kaon nucleon sigma terms. In the first phase of the experiment, dedicated to the calibration and optimization of the setup, the experiment collected data on gaseous kaonic nitrogen: for the first time a pattern of three transitions (7 → 6 at 4.6 keV, 6 → 5 at 7.6 keV and 5 → 4 at 14 keV) was measured, and the corresponding yields obtained. The kaonic hydrogen measurement followed, in the last months of 2002, for a total integrated luminosity of about 60 pb-1 . Data analyses are in progress, preliminary results being hereby presented, together with those on kaonic nitrogen. Future measurements: kaonic deuterium, kaonic helium and precise determination of the charged kaon mass are planned in the framework of the SIDDHARTA (SIlicon Drift Detector for Hadronic Atoms Research by Timing Application) experiment, which will replace DEAR on DAΦNE. [ABSTRACT FROM AUTHOR]