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Pichler A.,Stefan Meyer Institute For Subatomare Physik | Bartalucci S.,National Institute of Nuclear Physics, Italy | Bertolucci S.,CERN | Berucci C.,Stefan Meyer Institute For Subatomare Physik | And 33 more authors.
Hyperfine Interactions | Year: 2015

Many experiments investigated the violation of the Pauli Exclusion Principle (PEP) since its discovery in 1925. The VIP (VIolation of the Pauli Principle) experiment tested the PEP by measuring the probability for an external electron to be captured and undergo a 2p to 1s transition during its cascading process, where the 1s state is already occupied by two electrons. This transition is forbidden by the Pauli Exclusion Principle. The VIP experiment resulted in a preliminary upper limit for the probability of the violation of the PEP of 4.7×10−29. Currently a setup for the follow-up experiment VIP 2 is under preparation. The goal of this experiment is to improve the upper limit for the violation of the PEP by two orders of magnitude, by different improvements like enhanced energy resolution of the X-ray detectors and by implementing an active shielding. Here we report currently ongoing performance tests of the new parts of the setup. © 2015, Springer International Publishing Switzerland. Source


Bazzi M.,National Institute of Nuclear Physics, Italy | Beer G.,University of Victoria | Bellotti G.,Polytechnic of Milan | Bellotti G.,National Institute of Nuclear Physics, Italy | And 37 more authors.
Nuclear Physics A | Year: 2016

We measured the K-series X-rays of the K-p exotic atom in the SIDDHARTA experiment with a gaseous hydrogen target of 1.3 g/l, which is about 15 times the ρSTP of hydrogen gas. At this density, the absolute yields of kaonic X-rays, when a negatively charged kaon stopped inside the target, were determined to be 0.012-0.003+0.004 for Kα and 0.043-0.011+0.012 for all the K-series transitions Ktot. These results, together with the KEK E228 experiment results, confirm for the first time a target density dependence of the yield predicted by the cascade models, and provide valuable information to refine the parameters used in the cascade models for the kaonic atoms. © 2016 Elsevier B.V. Source


Shi H.,University of Tokyo | Bazzi M.,National Institute of Nuclear Physics, Italy | Beer G.,University of Victoria | Berucci C.,National Institute of Nuclear Physics, Italy | And 36 more authors.
EPJ Web of Conferences | Year: 2014

We measured K-series kaonic hydrogen X-rays in the SIDDHARTA experiment performed at the DAΦNE electron-positron collider of Laboratori Nazionali di Frascati. With a gaseous hydrogen target of density 15 ρSTP, 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 0.012-0.004+0.003 for Kα transition and 0.045-0.012+0.009 for Ktot, the summation of all the emitted K-series transitions. © Owned by the authors, published by EDP Sciences, 2013. Source

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