106 research outputs found
Special Issue on Spin Statistics
A workshop dedicated to spin statistics—"SpinStat2008"—was held at the end of October 2008 at the Stazione Marittima Conference Center in Trieste, Italy: it was meant to focus especially on experimental and theoretical aspects of the spin-statistics connection and of related symmetries (in particular the CPT and the Lorentz symmetries). The workshop was quite successful and everybody there felt that there should be a follow-up, and that the many interesting contributions and ideas presented there should be put in paper form. After some thinking we decided that the best format would be a series of refereed papers in a topical issue of an outstanding journal, open to all contributors, rather than the usual volume of conference papers restricted to participants. The Editors of Foundations of Physics kindly accepted to host this topical issue, and the ensuing call for papers drew a respectable flow of interesting and novel ideas, and some very appealing review papers. The comments that follow have bee
Snowmass 2021 Topical Report on Synergies in Research at Underground Facilities
This is a Snowmass 2021 Topical Report for the Underground Facilities and
Infrastructure Frontier on Synergies in Research at Underground Facilities: A
broad range of scientific and engineering research is possible in underground
laboratories, beyond the physics-focused activities described in the other
Underground Facilities and Infrastructure Topical Reports. These areas of
research include nuclear astrophysics, geology, geoengineering, gravitational
wave detection, biology, and perhaps soon quantum information science. This UF
Topical Report will survey those other scientific and engineering research
activities that share interest in research-orientated Underground Facilities
and Infrastructure. In most cases the breadth and depth of research aims is too
large to cover in completeness and references to surveys or key documents for
those fields are provided after introductory summaries. Additional attention is
then given to shared, similar, and unique needs of each research area with
respect to the broader underground research community's Underground Facilities
and Infrastructure needs. Where potential conflicts of usage type, site, or
duration might arise, these are identified.Comment: Snowmass 2021 Topical Report (UF5
Performances of an Active Target GEM-Based TPC for the AMADEUS Experiment
In this paper, we present the R & D activity on a new GEM-based Time Projection Chamber (GEM-TPC) detector for the inner region of the AMADEUS experiment, which is aiming to perform measurements of low-energy negative kaon interactions in nuclei at the DAΦNE e+ e- collider at LNF-INFN. A novel idea of using a GEM-TPC as a low mass target and detector at the same time comes motivated by the need of studying the low energy interactions of K- with nuclei in a complete way, tracking and identifying all of the produced particles. Even more, what makes the experimental proposal revolutionary is the possibility of using different gaseous targets without any other substantial intervention on the experimental setup, making it a flexible multipurpose device. This new detection technique applied to the nuclear physics requires the use of low-radiation length materials and very pure light gases such as Hydrogen, Deuterium, Helium-3, Helium-4, etc. In order to evaluate the GEM-TPC performances, a 10 × 10 cm2 prototype with a drift gap of 15 cm has been realized. The detector was tested at the πM1 beam facility of the Paul Scherrer Institut (PSI) with low momentum pions and protons. Detection efficiency and spatial resolution, as a function of gas mixture, gas gain and ionazing particle, are reported and discussed
Detecting Iron Oxidation States in Liquids with the VOXES Bragg Spectrometer
Determining the oxidation states of metals assumes great importance in
various applications because a variation in the oxidation number can
drastically influence the material properties. As an example, this becomes
evident in edible liquids like wine and oil, where a change in the oxidation
states of the contained metals can significantly modify both the overall
quality and taste. To this end, here we present the MITIQO project, which aims
to identify oxidation states of metals in edible liquids utilizing X-ray
emission with Bragg spectroscopy. This is achieved using the VOXES crystal
spectrometer, developed at INFN National Laboratories of Frascati (LNF),
employing mosaic crystal (HAPG) in the Von Hamos configuration. This
combination allow us to work with effective source sizes of up to a few
millimeters and improves the typical low efficiency of Bragg spectroscopy, a
crucial aspect when studying liquids with low metal concentration. Here we
showcase the concept behind MITIQO, for a liquid solution containing oxidized
iron. We performed several high-resolution emission spectra measurements, for
the liquid and for different powdered samples containing oxidized and pure
iron. By looking at the spectral features of the iron's K emission
lineshape, we were able to obtain, for a liquid, a result consistent with the
oxidized iron powders and successfully quantifying the effect of oxidation
Biophotons and emergence of quantum coherence : a diffusion entropy analysis
We study the emission of photons from germinating seeds using an experimental technique designed to detect light of extremely small intensity. We analyze the dark count signal without germinating seeds as well as the photon emission during the germination process. The technique of analysis adopted here, called diffusion entropy analysis (DEA) and originally designed to measure the temporal complexity of astrophysical, sociological and physiological processes, rests on Kolmogorov complexity. The updated version of DEA used in this paper is designed to determine if the signal complexity is generated either by non-ergodic crucial events with a non-stationary correlation function or by the infinite memory of a stationary but non-integrable correlation function or by a mixture of both processes. We find that dark count yields the ordinary scaling, thereby showing that no complexity of either kinds may occur without any seeds in the chamber. In the presence of seeds in the chamber anomalous scaling emerges, reminiscent of that found in neuro-physiological processes. However, this is a mixture of both processes and with the progress of germination the non-ergodic component tends to vanish and complexity becomes dominated by the stationary infinite memory. We illustrate some conjectures ranging from stress induced annihilation of crucial events to the emergence of quantum coherence
Studies of discrete symmetries in decays of positronium atoms
A positronium - a bound state of electron and positron - is an eigenstate of parity and charge conjugation operators which decays into photons. It is a unique laboratory to study discrete symmetries whose precision is limited, in principle, by the effects due to the weak interactions expected at the level of 10−14 and photon-photon interactions expected at the level of 10−9.
The Jagiellonian Positron Emission Tomograph (J-PET) is a detector for medical imaging as well as for physics studies involving detection of electronpositron annihilation into photons. The physics case covers the areas of discrete symmetries studies and genuine multipartite entanglement. The J-PET detector has high angular and time resolution and allows for determination of spin of the positronium and the momenta and polarization vectors of annihilation quanta. In this article, we present the potential of the J-PET system for studies of discrete symmetries in decays of positronium atoms
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