35 research outputs found

    Composite Dark Matter and Puzzles of Dark Matter Searches

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    Positive results of dark matter searches in DAMA/NaI and DAMA/LIBRA experiments, being put together with the results of other groups, can imply nontrivial particle physics solutions for cosmological dark matter. Stable particles with charge -2, bound with primordial helium in O-helium "atoms" (OHe), represent a specific Warmer than Cold nuclear-interacting form of dark matter. Slowed down in the terrestrial matter, OHe is elusive for direct methods of underground Dark matter detection used in cryogenic experiments. However radiative capture of OHe by Na and I nuclei can lead to annual variations of energy release in the interval of energy 2-5 keV in DAMA/NaI and DAMA/LIBRA experiments.Comment: 10 pages, 2 figures, Invited contribution to proceeding of the 4th International Workshop on Astronomy and Relativistic Astrophysics (IWARA09

    Towards Nuclear Physics of OHe Dark Matter

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    The nonbaryonic dark matter of the Universe can consist of new stable charged particles, bound in heavy "atoms" by ordinary Coulomb interaction. If stable particles OO^{--} with charge -2 are in excess over their antiparticles (with charge +2), the primordial helium, formed in Big Bang Nucleosynthesis, captures all OO^{--} in neutral "atoms" of O-helium (OHe). Interaction with nuclei plays crucial role in the cosmological evolution of OHe and in the effects of these dark atoms as nuclear interacting dark matter. Slowed down in terrestrial matter OHe atoms cause negligible effects of nuclear recoil in underground detectors, but can experience radiative capture by nuclei. Local concentration of OHe in the matter of detectors is rapidly adjusted to the incoming flux of cosmic OHe and possess annual modulation due to Earth's orbital motion around the Sun. The potential of OHe-nucleus interaction is determined by polarization of OHe by the Coulomb and nuclear force of the approaching nucleus. Stark-like effect by the Coulomb force of nucleus makes this potential attractive at larger distances, while change of polarization by the effect of nuclear force gives rise to a potential barrier, preventing merging of nucleus with helium shell of OHe atom. The existence of the corresponding shallow well beyond the nucleus can provide the conditions, at which nuclei in the matter of DAMA/NaI and DAMA/LIBRA detectors have a few keV binding energy with OHe, corresponding to a level in this well. Annual modulation of the radiative capture rate to this level can reproduce DAMA results. The OHe hypothesis can qualitatively explain the controversy in the results of direct dark matter searches by specifics of OHe nuclear interaction with the matter of underground detectors.Comment: to be published in Proceedings of XIV Bled Workshop "What comes beyond the Standard model?" (Bled, Slovenia

    ABOUT COMMON AND THEORETICAL INFORMATICS

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    In this article are considered the integrant importance of informatics and informational technologys includes the sciences and the humanities.There are a differences between scientifi c grounds of the various information orientations, which include physical informatics, bioinfomatics, technical and social informatics. Creation of a united theoretical base for these orientations is very problematical. The metodologically important issue of classifi cation different informatics is a part of the general informatics, the example of which are considered here

    CLASSIFICATION OF INFORMATICS AND INFORMATION TECHNOLOGIES

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    The article considers the actual question about informatics and information technologies classifi cation. There are the hegemony information technologies over the information sciences and two modern methods of classifi cation: “habitatual” and “conceptual-criterial” method. On the basis of the last the article calls attention to example for classifi cation of science’s nomenclature of VAK

    Puzzles of Dark Matter - More Light on Dark Atoms?

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    Positive results of dark matter searches in experiments DAMA/NaI and DAMA/LIBRA confronted with results of other groups can imply nontrivial particle physics solutions for cosmological dark matter. Stable particles with charge -2, bound with primordial helium in O-helium "atoms" (OHe), represent a specific nuclear-interacting form of dark matter. Slowed down in the terrestrial matter, OHe is elusive for direct methods of underground Dark matter detection using its nuclear recoil. However, low energy binding of OHe with sodium nuclei can lead to annual variations of energy release from OHe radiative capture in the interval of energy 2-4 keV in DAMA/NaI and DAMA/LIBRA experiments. At nuclear parameters, reproducing DAMA results, the energy release predicted for detectors with chemical content other than NaI differ in the most cases from the one in DAMA detector. Moreover there is no bound systems of OHe with light and heavy nuclei, so that there is no radiative capture of OHe in detectors with xenon or helium content. Due to dipole Coulomb barrier, transitions to more energetic levels of Na+OHe system with much higher energy release are suppressed in the correspondence with the results of DAMA experiments. The proposed explanation inevitably leads to prediction of abundance of anomalous Na, corresponding to the signal, observed by DAMA.Comment: Contribution to Proceedings of XIII Bled Workshop "What Comes beyond the Standard Model?

    Gate-defined quantum confinement in InSe-based van der Waals heterostructures

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    Indium selenide, a post-transition metal chalcogenide, is a novel two-dimensional (2D) semiconductor with interesting electronic properties. Its tunable band gap and high electron mobility have already attracted considerable research interest. Here we demonstrate strong quantum confinement and manipulation of single electrons in devices made from few-layer crystals of InSe using electrostatic gating. We report on gate-controlled quantum dots in the Coulomb blockade regime as well as one-dimensional quantization in point contacts, revealing multiple plateaus. The work represents an important milestone in the development of quality devices based on 2D materials and makes InSe a prime candidate for relevant electronic and optoelectronic applications
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