1,592 research outputs found
Breaks in interstellar spectra of positrons and electrons derived from time-dependent AMS data
Until fairly recently, it was widely accepted that local cosmic ray spectra
were largely featureless power laws, containing limited information on their
acceleration and transport. This viewpoint is currently being revised in the
light of evidence for a variety of spectral breaks in the fluxes of cosmic ray
nuclei. Here, we focus on cosmic ray electrons and positrons which at the
highest energies must be of local origin due to strong radiative losses. We
consider a pure diffusion model for their Galactic transport and determine its
free parameters by fitting data in a wide energy range: measurements of the
interstellar spectrum by Voyager at MeV energies, radio synchrotron data
(sensitive to GeV electrons and positrons) and local observations by AMS up to
~ 1 TeV. For the first time, we also model the time-dependent fluxes of cosmic
ray electrons and positrons at GeV energies recently presented by AMS, treating
solar modulation in a simple extension of the widely used force-field
approximation. We are able to reproduce all the available measurements to date.
Our model of the interstellar spectrum of cosmic ray electrons and positrons
requires the presence of a number of spectral breaks, both in the source
spectra and the diffusion coefficients. While we remain agnostic as to the
origin of these spectral breaks, their presence will inform future models of
the microphysics of cosmic ray acceleration and transport.Comment: 19 pages, 9 figures; submitted to PR
Constraints on leptophilic dark matter from the AMS-02 experiment
The annihilation of dark matter particles in the galactic halo of the Milky
Way may lead to cosmic ray signatures that can be probed by the AMS-02
experiment, which has measured the composition and fluxes of charged cosmic
rays with unprecedented precision. Given the absence of characteristic spectral
features in the electron and positron fluxes measured by AMS-02, we derive
upper limits on the dark matter annihilation cross section for leptophilic dark
matter models. Our limits are based on a new background model that describes
all recent measurements of the energy spectra of cosmic ray positrons and
electrons. For thermal dark matter relics, we can exclude dark matter masses
below about 100 GeV. We include the radiation of electroweak gauge bosons in
the dark matter annihilation process and compute the antiproton signal that can
be expected within leptophilic dark matter models.Comment: 7 pages, 3 figures, 1 table. Matches the published version apart from
typo corrected in Eq.
Monte Carlo Simulations of the Transition Radiation Detector of the AMS-02 Experiment
The Transition Radiation Detector of the AMS-02 experiment on the
International Space Station is used for the separation of cosmic-ray positrons
and electrons from protons and anti-protons, and for the identification of
nuclei up to carbon (Z<=6). We present the Geant4 simulation that is used to
describe the ionization and transition radiation processes and compare its
results to flight data from AMS-02. After applying empirical corrections to the
simulated data, the particle energy deposition and likelihood distributions in
the TRD are described with high accuracy.Comment: 7 pages, 9 figures. Accepted for publication in Nuclear Inst. and
Methods in Physics Research, A. CC-BY-NC-ND 4.0 licens
ΠΡΠΎΠ²Π΅Π΄Π΅Π½ΠΈΠ΅ ΡΠ΅ΡΠΌΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ Π°Π½Π°Π»ΠΈΠ·Π° ΡΠ³Π»Π΅ΡΠΎΠ΄Π½ΡΡ ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡΠΈΠΉ Ρ ΠΏΠΎΠΌΠΎΡΡΡ ΠΏΡΠΎΠ³ΡΠ°ΠΌΠΌΠ½ΠΎΠ³ΠΎ ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠ΅Π½ΠΈΡ SolidWorks
ΠΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠΎΠ½Π½Π°Ρ ΡΠΈΡΡΠ΅ΠΌΠ° ΡΡΠ΅ΡΠ° ΠΈ Π°Π½Π°Π»ΠΈΠ·Π° Π΄Π΅ΡΡΠ΅Π»ΡΠ½ΠΎΡΡΠΈ ΠΌΠ°Π³Π°Π·ΠΈΠ½Π° ΠΏΠΎ ΠΏΡΠΎΠ΄Π°ΠΆΠ΅ ΠΌΡΠ³ΠΊΠΎΠΉ ΠΌΠ΅Π±Π΅Π»ΠΈ
ΠΠ±ΡΠ΅ΠΊΡΠΎΠΌ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ ΡΠ²Π»ΡΠ΅ΡΡΡ ΠΏΡΠΎΡΠ΅ΡΡ ΡΡΠ΅ΡΠ° ΠΈ Π°Π½Π°Π»ΠΈΠ·Π° Π΄Π΅ΡΡΠ΅Π»ΡΠ½ΠΎΡΡΠΈ ΠΌΠ°Π³Π°Π·ΠΈΠ½Π° ΠΏΠΎ ΠΏΡΠΎΠ΄Π°ΠΆΠ΅ ΠΌΡΠ³ΠΊΠΎΠΉ ΠΌΠ΅Π±Π΅Π»ΠΈ ΠΠΠ "Π‘ΠΈΠ±ΠΈΡΡΠΊΠ°Ρ ΠΌΠ΅Π±Π΅Π»ΡΠ½Π°Ρ ΠΊΠΎΠΌΠΏΠ°Π½ΠΈΡ".
Π¦Π΅Π»Ρ ΡΠ°Π±ΠΎΡΡ β ΡΠ°Π·ΡΠ°Π±ΠΎΡΠΊΠ° ΠΠ‘ ΡΡΠ΅ΡΠ° ΠΈ Π°Π½Π°Π»ΠΈΠ·Π° Π΄Π΅ΡΡΠ΅Π»ΡΠ½ΠΎΡΡΠΈ ΠΌΠ°Π³Π°Π·ΠΈΠ½Π° ΠΏΠΎ ΠΏΡΠΎΠ΄Π°ΠΆΠ΅ ΠΌΡΠ³ΠΊΠΎΠΉ ΠΌΠ΅Π±Π΅Π»ΠΈ Π΄Π»Ρ ΠΠΠ "Π‘ΠΈΠ±ΠΈΡΡΠΊΠ°Ρ ΠΌΠ΅Π±Π΅Π»ΡΠ½Π°Ρ ΠΊΠΎΠΌΠΏΠ°Π½ΠΈΡ".
Π ΠΏΡΠΎΡΠ΅ΡΡΠ΅ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ ΠΈΠ·ΡΡΠ΅Π½Ρ ΠΎΡΠ³Π°Π½ΠΈΠ·Π°ΡΠΈΠΎΠ½Π½Π°Ρ ΡΡΡΡΠΊΡΡΡΠ° ΠΈ Π΄ΠΎΠΊΡΠΌΠ΅Π½ΡΠΎΠΎΠ±ΠΎΡΠΎΡ ΠΠΠ "Π‘ΠΈΠ±ΠΈΡΡΠΊΠ°Ρ ΠΌΠ΅Π±Π΅Π»ΡΠ½Π°Ρ ΠΊΠΎΠΌΠΏΠ°Π½ΠΈΡ". ΠΡΠΎΠ²Π΅Π΄Π΅Π½ ΡΠ΅ΠΎΡΠ΅ΡΠΈΡΠ΅ΡΠΊΠΈΠΉ Π°Π½Π°Π»ΠΈΠ· ΠΏΡΠ΅Π΄ΠΌΠ΅ΡΠ½ΠΎΠΉ ΠΎΠ±Π»Π°ΡΡΠΈ, ΠΎΠ±Π·ΠΎΡ Π°Π½Π°Π»ΠΎΠ³ΠΎΠ² ΡΠ°Π·ΡΠ°Π±Π°ΡΡΠ²Π°Π΅ΠΌΠΎΠΉ ΠΠ‘, ΡΠΏΡΠΎΠ΅ΠΊΡΠΈΡΠΎΠ²Π°Π½Π° ΠΈ ΡΠ°Π·ΡΠ°Π±ΠΎΡΠ°Π½Π° ΠΠ‘, ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½ Π°Π½Π°Π»ΠΈΠ· Π²ΡΠ΅Π΄Π½ΡΡ
ΡΠ°ΠΊΡΠΎΡΠΎΠ² Π½Π° ΡΠ°Π±ΠΎΡΠ΅ΠΌ ΠΌΠ΅ΡΡΠ΅ ΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°ΡΠ΅Π»Π΅ΠΉ.The process of accounting and analysis of the LLC "Siberian Furniture Company" furniture store's activities is the object of the study.
The purpose of the work is to develop an information system for accounting and analysis of the LLC "Siberian Furniture Company" furniture store's activities.
In the course of the study, the organizational structure and document flow of LLC "Siberian Furniture Company" were studied. A theoretical analysis of the subject area, a review of the analogues of the developed information system, an information system is designed and developed, an analysis of harmful factors in the workplace of users is carried out
Yukawa unification in SO(10) with light sparticle spectrum
We investigate supersymmetric SO(10) GUT model with \mu<0. The requirements
of top-bottom-tau Yukawa unification, correct radiative electroweak symmetry
breaking and agreement with the present experimental data may be met when the
soft masses of scalars and gauginos are non-universal. We show how appropriate
non-universalities can easily be obtained in the SO(10) GUT broken to the
Standard Model. We discuss how values of BR(b-->s \gamma) and (g-2)_\mu
simultaneously in a good agreement with the experimental data can be achieved
in SO(10) model with \mu<0. In the region of the parameter space preferred by
our analysis there are two main mechanisms leading to the LSP relic abundance
consistent with the WMAP results. One is the co-annihilation with the stau and
the second is the resonant annihilation via exchange of the Z boson or the
light Higgs scalar. A very interesting feature of SO(10) models with negative
\mu is that they predict relatively light sparticle spectra. Even the heaviest
superpartners may easily have masses below 1.5 TeV in contrast to multi-TeV
particles typical for models with positive \mu.Comment: 23 pages, 5 figure
ΠΠΎΠΌΠ±ΠΈΠ½ΠΈΡΠΎΠ²Π°Π½Π½ΡΠΉ ΡΠΎΡΠΎΡΠ»Π΅ΠΊΡΡΠΈΡΠ΅ΡΠΊΠΈΠΉ ΡΠΏΠΎΡΠΎΠ± ΠΈΠ·ΠΌΠ΅ΡΠ΅Π½ΠΈΡ ΠΊΠΎΠ½ΡΠ΅Π½ΡΡΠ°ΡΠΈΠΉ Π²Π΅ΡΠ΅ΡΡΠ²
Inverted sfermion mass hierarchy and the Higgs boson mass in the MSSM
It is shown that MSSM with first two generations of squarks and sleptons much
heavier than the third one naturally predicts the maximal stop mixing as a
consequence of the RG evolution, with vanishing (or small) trilinear coupling
at the high scale. The Higgs boson is generically heavy, in the vicinity of 125
GeV. In this inverted hierarchy scenario, motivated by the supersymmetric FCNC
problem and models for fermion masses based on horizontal symmetries, the mass
of the lightest stop is O(0.5) TeV and of gluino - O(2-3) TeV. The LSP can be
either higgsino or bino or a mixture of both and it can be a good dark matter
candidate.Comment: 22 pages, 8 figures, comments and references adde
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