VIP-2 —High-Sensitivity Tests on the Pauli Exclusion Principle for Electrons

The VIP collaboration is performing high sensitivity tests of the Pauli Exclusion Principle for electrons in the extremely low cosmic background environment of the underground Gran Sasso National Laboratory INFN (Italy). In particular, the VIP-2 Open Systems experiment was conceived to put strong constraints on those Pauli Exclusion Principle violation models which respect the so-called Messiah–Greenberg superselection rule. The experimental technique consists of introducing a direct current in a copper conductor, and searching for the X-rays emission coming from a forbidden atomic transition from the L shell to the K shell of copper when the K shell is already occupied by two electrons. The analysis of the first three months of collected data (in 2018) is presented. The obtained result represents the best bound on the Pauli Exclusion Principle violation probability which fulfills the Messiah–Greenberg rule

HIGH SENSITIVITY QUANTUM MECHANICS TESTS IN THE COSMIC SILENCE

The VIP experiment aims to perform high-precision tests of the Pauli Exclusion Principle for electrons in the extremely low cosmic background environment of the Underground Gran Sasso Laboratories of INFN (Italy). The experimental technique consists in introducing a DC current in a copper conductor, searching for K α PEP-forbidden atomic transitions when the K shell is already occupied by two electrons. The results of a preliminary data analysis, corresponding to the first run of the VIP-2 data taking (2016–2017), are presented. The experimental setup in the final configuration is described together with preliminary spectra from the 2019 data-taking campaign

Test of the Pauli Exclusion Principle in the VIP-2 Underground Experiment

The validity of the Pauli exclusion principle\u2014a building block of Quantum Mechanics\u2014is tested for electrons. The VIP (violation of Pauli exclusion principle) and its follow-up VIP-2 experiments at the Laboratori Nazionali del Gran Sasso search for X-rays from copper atomic transitions that are prohibited by the Pauli exclusion principle. The candidate events\u2014if they exist\u2014originate from the transition of a 2p orbit electron to the ground state which is already occupied by two electrons. The present limit on the probability for Pauli exclusion principle violation for electrons set by the VIP experiment is 4.7 710^ 1229. We report a first result from the VIP-2 experiment improving on the VIP limit, which solidifies the final goal of achieving a two orders of magnitude gain in the long run

High Precision Test of the Pauli Exclusion Principle for Electrons

The VIP-2 experiment aims to perform high precision tests of the Pauli Exclusion Principle for electrons. The method consists in circulating a continuous current in a copper strip, searching for the X radiation emission due to a prohibited transition (from the 2p level to the 1s level of copper when this is already occupied by two electrons). VIP already set the best limit on the PEP violation probability for electrons $\frac{1}{2} \beta^2 < 4.7 \times 10^{-29}$, the goal of the upgraded VIP-2 (VIolation of the Pauli Exclusion Principle-2) experiment is to improve this result of two orders of magnitude at least. The experimental apparatus and the results of the analysis of a first set of collected data will be presented

Search for a remnant violation of the Pauli exclusion principle in a Roman lead target

In this paper we report on the results of two analyses of the data taken with a dedicated VIP-Lead experiment at the Gran Sasso National Laboratory of the INFN. We use measurements taken in an environment that is especially well screened from cosmic rays, with a metal target made of “Roman lead” which is characterised by a low level of intrinsic radioactivity. The analyses lead to an improvement, on the upper bounds of the Pauli Exclusion Principle violation for electrons, which is more than one (four) orders of magnitude, when the electron-atom interactions are described in terms of scatterings (or close encounters) respectively

NEW CONCEPTS IN TESTS OF THE PAULI EXCLUSION PRINCIPLE IN BULK MATTER

The standard scheme of several tests of the Pauli Exclusion Principle in bulk matter — both in the experiment and in the subsequent data analysis — has long been based on the seminal paper by E. Ramberg, G.A. Snow [Phys. Lett. B 238, 438 (1990)]. The ideas exposed in that paper are so simple and immediate that they have long gone unchallenged. However, while some of the underlying approximations are still valid, other parts of the article must be reconsidered. Here, we discuss some new concepts that are related to the motion of the electrons in the test metal (the “target” of the experiment) and which have been recently studied in the framework of the VIP-2 Collaboration

High precision kaonic deuterium measurement at the DAΦNE collider : the SIDDHARTA-2 experiment and the SIDDHARTINO run

The kaonic deuterium 2p → 1s transition X-ray measurement, a fundamental information needed for a deeper understanding of the Quantum ChromoDynamics (QCD) in the strangeness sector, is still missing. The SIDDHARTA-2 collaboration is now ready to achieve this unprecedented result thanks to the dedicated experimental apparatus that will allow to obtain the values of the kaonic deuterium K-transitions with a precision comparable to the most precise kaonic hydrogen measurement to-date performed by SIDDHARTA in 2009. Both the kaonic hydrogen and kaonic deuterium X-ray spectroscopy measurements of the de-excitation towards the fundamental level are a direct probe on KN interaction at threshold, as opposed to the scattering experiments which need an extrapolation to zero energy. Combining these results through the Deser-Truemann like formula, the isospin-dependent kaon-nucleon scattering lengths can be obtained in a model-independent way. The SIDDHARTA-2 setup is presently installed at the DAΦNE (Double Annular Φ Factory for Nice Experiments) collider of Istituto Nazionale di Fisica Nucleare – Laboratori Nazionali di Frascati and it is ready to perform the challening kaonic deuterium measurement. This paper provides an overview on the SIDDHARTA-2 experimental apparatus and a preliminary result of the kaonic helium run, preparatory for the SIDDHARTA-2 data taking campaign, is also presented

Kaonic atoms measurements at the DAΦNE collider : the SIDDHARTA-2 experiment

The X-ray spectroscopy measurements of light kaonic atoms’ deexcitation towards the fundamental level provide unique information on the low-energy Quantum ChromoDynamics (QCD) in the strangeness sector, being a direct probe of the kaon/nucleon interaction at threshold, unobtainable through the scattering experiments. In this framework, the SIDDHARTA-2 collaboration is going to perform the first kaonic deuterium 2p $\to$ 1s transition measurement at the DAΦNE collider of Istituto Nazionale di Fisica Nucleare – Laboratori Nazionali di Frascati. Combining this measurement with the kaonic hydrogen one performed by SIDDHARTA in 2009 it will be possible to obtain, in a model-independent way, the isospin-dependent antikaon-nucleon scattering lengths. The paper introduces the SIDDHARTA-2 setup, an upgraded version with respect to the one used for the kaonic hydrogen measurement, dedicated to the ambitious kaonic deuterium measurement, together with the preliminary results obtained during the kaonic helium run, preparatory for the SIDDHARTA-2 data taking campaign