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.
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.
Violations of the Pauli Exclusion Principle (PEP), albeit small, could be motivated by physics beyond the Standard Model, ranging from violation of Lorentz invariance to extra space dimensions. This ...scenario can be experimentally constrained through dedicated, state-of-the-art X-ray spectroscopy, searching for a forbidden atomic transition from the L shell to the K shell already occupied by two electrons. The VIP-2 Experiment located at the underground Gran Sasso National Laboratories of INFN (Italy) tests PEP violations by introducing new electrons via a direct current in a copper conductor, measuring the X-ray energies through a silicon drift detector. Bayesian and frequentist analyses of approximately six months of data taken with the fully operational setup is presented, setting the strongest limit to date on the PEP violation shown by the VIP collaboration. The upper bound on PEP violation are placed at 90% CL β2/2≤6.8×10−42 with the Bayesian approach, and β2/2≤7.1×10−42 with the frequentist CLs technique.
VIP-2 (VIolation of Pauli exclusion principle - 2) is an underground experiment sited in the underground “Laboratori Nazionali del Gran Sasso.” It aims to investigate possible violations of the Pauli ...Exclusion Principle (PEP) and, in this context, Quantum Gravity models implying violations of PEP. While an upper limit of PEP violation probability is recently published, the data requires further developments of accurate analysis techniques and methods. In this contribution, we present an overview of the methodologies proposed for current and planned analysis.
The VIolation of Pauli (VIP) experiment (and its upgraded version, VIP-2) uses the Ramberg and Snow (RS) method (Phys. Lett. B 1990, 238, 438) to search for violations of the Pauli exclusion ...principle in the Gran Sasso underground laboratory. The RS method consists of feeding a copper conductor with a high direct current, so that the large number of newly-injected conduction electrons can interact with the copper atoms and possibly cascade electromagnetically to an already occupied atomic ground state if their wavefunction has the wrong symmetry with respect to the atomic electrons, emitting characteristic X-rays as they do so. In their original data analysis, RS considered a very simple path for each electron, which is sure to return a bound, albeit a very weak one, because it ignores the meandering random walks of the electrons as they move from the entrance to the exit of the copper sample. These complex walks bring the electrons close to many more atoms than in the RS calculation. Here, we consider the full description of these walks and show that this leads to a nontrivial and nonlinear X-ray emission rate. Finally, we obtain an improved bound, which sets much tighter constraints on the violation of the Pauli exclusion principle for electrons.
Gravitational lensing of invisible streaming matter towards the Sun or the Earth could be the explanation of puzzling solar/terrestrial phenomena. We have analyzed solar flares, EUV emission and also ...the global ionization content of the Earth atmosphere. Assuming that this invisible matter has some form of interaction with normal matter and that there exist preferred directions in its flow, then one would expect an enhanced activity at certain planetary longitudes, which is also observed. The broad velocity spectrum of the assumed constituents makes it difficult at this stage to identify the origin of the stream(s) or the nature of its constituents.
The VIP-2 collaboration runs an apparatus in the Gran Sasso underground laboratories of the Italian Institute for Nuclear Physics (INFN) designed to search for anomalous X-rays from electron-atom ...interactions due to violations of the fundamental antisymmetry of multi-electron wavefunctions. The experiment implements the scheme first proposed by Ramberg and Snow, where a current source injects electrons into a metal strip (the experiment’s target). In this paper we describe the structure of a Monte Carlo program to simulate a new upgrade of the experiment, where the anomalous X-ray emission is modulated by an arbitrary time-varying input current. A novel feature of the simulation algorithm is that the Monte Carlo program is based on a mixture of analytical and numerical methods. We report preliminary, exploratory results on the expected detection rate for different modulations of the injected current; these results are a starting point on the way to optimize the modulation scheme and indicate a large potential improvement of the detection sensitivity.
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 1 2 β 2 < 4.7 × 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.
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