35 research outputs found
Composite Dark Matter and Puzzles of Dark Matter Searches
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
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 with charge -2 are in excess over their antiparticles (with
charge +2), the primordial helium, formed in Big Bang Nucleosynthesis, captures
all 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
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
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?
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
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
Diabetes mellitus type 1 in childhood
Public organization “Russian Association of Endocrinologists”. Clinical guidlines