5,625 research outputs found
Giant dispersion of critical currents in superconductor with fractal clusters of a normal phase
The influence of fractal clusters of a normal phase on the dynamics of a
magnetic flux trapped in a percolative superconductor is considered. The
critical current distribution and the current-voltage characteristics of
fractal superconducting structures in the resistive state are obtained for an
arbitrary fractal dimension of the cluster boundaries. The range of fractal
dimensions, where the dispersion of critical currents becomes infinite, is
found. It is revealed that the fractality of clusters depresses of the electric
field caused by the magnetic flux motion thus increasing the critical current
value. It is expected that the maximum current-carrying capability of a
superconductor can be achieved in the region of giant dispersion of critical
currents.Comment: 7 pages with 3 figure
Realistic calculations of nuclear disappearance lifetimes induced by neutron-antineutron oscillations
Realistic calculations of nuclear disappearance lifetimes induced by
neutron-antineutron oscillations are reported for oxygen and iron, using
antineutron nuclear potentials derived from a recent comprehensive analysis of
antiproton atomic X-ray and radiochemical data. A lower limit of 3.3 x 10E8 s
on the neutron-antineutron oscillation time is derived from the
Super-Kamiokande I new lower limit of 1.77 x 10E32 yr on the neutron lifetime
in oxygen. Antineutron scattering lengths in carbon and nickel, needed in trap
experiments using ultracold neutrons, are calculated from updated antinucleon
optical potentials at threshold, with results shown to be largely model
independent.Comment: version matching PRD publication, typos and references correcte
Cosmic Coincidence and Asymmetric Dark Matter in a Stueckelberg Extension
We discuss the possibility of cogenesis generating the ratio of baryon
asymmetry to dark matter in a Stueckelberg U(1) extension of the standard model
and of the minimal supersymmetric standard model. For the U(1) we choose
which is anomaly free and can be gauged. The dark matter
candidate arising from this extension is a singlet of the standard model gauge
group but is charged under . Solutions to the Boltzmann
equations for relics in the presence of asymmetric dark matter are discussed.
It is shown that the ratio of the baryon asymmetry to dark matter consistent
with the current WMAP data, i.e., the cosmic coincidence, can be successfully
explained in this model with the depletion of the symmetric component of dark
matter from resonant annihilation via the Stueckelberg gauge boson. For the
extended MSSM model it is shown that one has a two component dark matter
picture with asymmetric dark matter being the dominant component and the
neutralino being the subdominant component (i.e., with relic density a small
fraction of the WMAP cold dark matter value). Remarkably, the subdominant
component can be detected in direct detection experiments such as SuperCDMS and
XENON-100. Further, it is shown that the class of Stueckelberg models with a
gauged will produce a dramatic signature at a muon collider
with the showing a detectable
resonance while is devoid of this
resonance. Asymmetric dark matter arising from a Stueckelberg
extension is also briefly discussed. Finally, in the models we propose the
asymmetric dark matter does not oscillate and there is no danger of it being
washed out from oscillations.Comment: 36 pages, 7 figure
ΠΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠΎΠ½Π½Π°Ρ ΠΏΠΎΠ΄Π΄Π΅ΡΠΆΠΊΠ° Π°Π½Π°Π»ΠΈΠ·Π° Π½Π°Π²ΡΠΊΠΎΠ² ΠΈ ΡΠΌΠ΅Π½ΠΈΠΉ ΠΊΠΎΠ½ΡΠΈΠ½Π³Π΅Π½ΡΠ° ΡΡΡΠ΄Π΅Π½ΡΠΎΠ² Π²ΡΡΡΠ΅Π³ΠΎ ΡΡΠ΅Π±Π½ΠΎΠ³ΠΎ Π·Π°Π²Π΅Π΄Π΅Π½ΠΈΡ
In the below article, the application of the fuzzy logical conclusion method is considered as decision-maker in the process of analyzing the students skills and abilities based on the requirements of potential employers, in order to reduce the time of the first interview for potential candidates on a vacant position. When analyzing the results of the assessment of the competence of university students, a certain degree of fuzziness arises. In modern practice, fuzzy logic is used in many different assessment methods, including questioning, interviewing, testing, descriptive method, classification method, pairwise comparison, rating method, business games competence models, and the like. Each of the methods has its advantages and disadvantages, but they are effective only as part of a unified personnel management system. As a method for implementing a systematic approach to the assessment of the contingent of students, it is proposed to use fuzzy logic, a mathematical apparatus that allows you to build a model of an object based on fuzzy judgments. The use of fuzzy logic, the mathematical apparatus of which allows you to build a model of the object, based on fuzzy reasoning and rules. The most important condition for creating such a model is to translate the fuzzy, qualitative assessments used by man into the language of mathematics, which will be understood by the computer. The most used are fuzzy inferences using the Mamdani and Sugeno methods. In a fuzzy inference of the Mamdani type, the value of the output variable is given by fuzzy terms, in the conclusion of the Sugeno type, as a linear combination of the input variables. Research in the field of application of fuzzy logic in socio-economic systems suggests that it can be used to assess the competencies of university students.Π Π΄Π°Π½Π½ΠΎΠΉ ΡΠ°Π±ΠΎΡΠ΅ ΡΠ°ΡΡΠΌΠΎΡΡΠ΅Π½ΠΎ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΠ΅ ΠΌΠ΅ΡΠΎΠ΄Π° Π½Π΅ΡΠ΅ΡΠΊΠΎΠ³ΠΎ Π»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ Π²ΡΠ²ΠΎΠ΄Π° Π΄Π»Ρ ΠΏΠΎΠ΄Π΄Π΅ΡΠΆΠΊΠΈ ΠΏΡΠΈΠ½ΡΡΠΈΡ ΡΠ΅ΡΠ΅Π½ΠΈΡ Π² Π·Π°Π΄Π°ΡΠ°Ρ
Π°Π½Π°Π»ΠΈΠ·Π° Π½Π°Π²ΡΠΊΠΎΠ² ΠΈ ΡΠΌΠ΅Π½ΠΈΠΉ ΠΊΠΎΠ½ΡΠΈΠ½Π³Π΅Π½ΡΠ° ΡΡΡΠ΄Π΅Π½ΡΠΎΠ² ΠΈΡΡ
ΠΎΠ΄Ρ ΠΈΠ· ΡΡΠ΅Π±ΠΎΠ²Π°Π½ΠΈΠΉ ΠΏΠΎΡΠ΅Π½ΡΠΈΠ°Π»ΡΠ½ΡΡ
ΡΠ°Π±ΠΎΡΠΎΠ΄Π°ΡΠ΅Π»Π΅ΠΉ, Ρ ΡΠ΅Π»ΡΡ ΡΠΌΠ΅Π½ΡΡΠ΅Π½ΠΈΡ Π²ΡΠ΅ΠΌΠ΅Π½ΠΈ Π½Π° ΠΏΠ΅ΡΠ²ΠΈΡΠ½ΡΡ ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΡ ΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠΈ ΠΊΠ°ΡΠ°ΡΠ΅Π»ΡΠ½ΠΎ ΠΏΠΎΡΠ΅Π½ΡΠΈΠ°Π»ΡΠ½ΡΡ
ΠΊΠ°Π½Π΄ΠΈΠ΄Π°ΡΠΎΠ² Π½Π° Π²Π°ΠΊΠ°Π½ΡΠ½ΡΡ Π΄ΠΎΠ»ΠΆΠ½ΠΎΡΡΡ. ΠΡΠΈ Π°Π½Π°Π»ΠΈΠ·Π΅ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠΎΠ² ΠΎΡΠ΅Π½ΠΊΠΈ ΠΊΠΎΠΌΠΏΠ΅ΡΠ΅Π½ΡΠ½ΠΎΡΡΠΈ ΡΡΡΠ΄Π΅Π½ΡΠΎΠ² Π²ΡΠ·ΠΎΠ² Π²ΠΎΠ·Π½ΠΈΠΊΠ°Π΅Ρ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Π½Π°Ρ ΡΡΠ΅ΠΏΠ΅Π½Ρ Π½Π΅ΡΠ΅ΡΠΊΠΎΡΡΠΈ. Π ΡΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΠΎΠΉ ΠΏΡΠ°ΠΊΡΠΈΠΊΠ΅ Π½Π΅ΡΠ΅ΡΠΊΠ°Ρ Π»ΠΎΠ³ΠΈΠΊΠ° ΠΏΡΠΈΠΌΠ΅Π½ΡΠ΅ΡΡΡ Π²ΠΎ ΠΌΠ½ΠΎΠ³ΠΈΡ
ΡΠ°Π·Π»ΠΈΡΠ½ΡΡ
ΠΌΠ΅ΡΠΎΠ΄Π°Ρ
ΠΎΡΠ΅Π½ΠΊΠΈ, Π² ΡΠΎΠΌ ΡΠΈΡΠ»Π΅ Π°Π½ΠΊΠ΅ΡΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅, ΠΈΠ½ΡΠ΅ΡΠ²ΡΡ, ΡΠ΅ΡΡΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅, ΠΎΠΏΠΈΡΠ°ΡΠ΅Π»ΡΠ½ΡΠΉ ΠΌΠ΅ΡΠΎΠ΄, ΠΌΠ΅ΡΠΎΠ΄ ΠΊΠ»Π°ΡΡΠΈΡΠΈΠΊΠ°ΡΠΈΠΈ, ΠΏΠ°ΡΠ½ΠΎΠ΅ ΡΡΠ°Π²Π½Π΅Π½ΠΈΠ΅, ΡΠ΅ΠΉΡΠΈΠ½Π³ΠΎΠ²ΡΠΉ ΠΌΠ΅ΡΠΎΠ΄, Π΄Π΅Π»ΠΎΠ²ΡΠ΅ ΠΈΠ³ΡΡ ΠΌΠΎΠ΄Π΅Π»ΠΈ ΠΊΠΎΠΌΠΏΠ΅ΡΠ΅Π½ΡΠ½ΠΎΡΡΠΈ ΠΈ ΡΠΎΠΌΡ ΠΏΠΎΠ΄ΠΎΠ±Π½ΠΎΠ΅. ΠΠ°ΠΆΠ΄ΡΠΉ ΠΈΠ· ΠΌΠ΅ΡΠΎΠ΄ΠΎΠ² ΠΈΠΌΠ΅Π΅Ρ ΡΠ²ΠΎΠΈ ΠΏΡΠ΅ΠΈΠΌΡΡΠ΅ΡΡΠ²Π° ΠΈ Π½Π΅Π΄ΠΎΡΡΠ°ΡΠΊΠΈ, Π½ΠΎ ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½Ρ ΠΎΠ½ΠΈ ΡΠΎΠ»ΡΠΊΠΎ Π² ΡΠΎΡΡΠ°Π²Π΅ Π΅Π΄ΠΈΠ½ΠΎΠΉ ΡΠΈΡΡΠ΅ΠΌΡ ΡΠΏΡΠ°Π²Π»Π΅Π½ΠΈΡ ΠΏΠ΅ΡΡΠΎΠ½Π°Π»ΠΎΠΌ. ΠΠ°ΠΊ ΠΌΠ΅ΡΠΎΠ΄ Π΄Π»Ρ ΡΠ΅Π°Π»ΠΈΠ·Π°ΡΠΈΠΈ ΡΠΈΡΡΠ΅ΠΌΠ½ΠΎΠ³ΠΎ ΠΏΠΎΠ΄Ρ
ΠΎΠ΄Π° ΠΊ ΠΎΡΠ΅Π½ΠΊΠ΅ ΠΊΠΎΠ½ΡΠΈΠ½Π³Π΅Π½ΡΠ° ΡΡΡΠ΄Π΅Π½ΡΠΎΠ² ΠΏΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½ΠΎ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°ΡΡ Π½Π΅ΡΠ΅ΡΠΊΡΡ Π»ΠΎΠ³ΠΈΠΊΡ, ΠΌΠ°ΡΠ΅ΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΈΠΉ Π°ΠΏΠΏΠ°ΡΠ°Ρ, ΠΊΠΎΡΠΎΡΡΠΉ ΠΏΠΎΠ·Π²ΠΎΠ»ΡΠ΅Ρ ΠΏΠΎΡΡΡΠΎΠΈΡΡ ΠΌΠΎΠ΄Π΅Π»Ρ ΠΎΠ±ΡΠ΅ΠΊΡΠ°, ΠΎΡΠ½ΠΎΠ²Π°Π½Π½ΡΡ Π½Π° Π½Π΅ΡΠ΅ΡΠΊΠΈΡ
ΡΡΠΆΠ΄Π΅Π½ΠΈΡΡ
. ΠΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΠ΅ Π½Π΅ΡΠ΅ΡΠΊΠΎΠΉ Π»ΠΎΠ³ΠΈΠΊΠΈ, ΠΌΠ°ΡΠ΅ΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΈΠΉ Π°ΠΏΠΏΠ°ΡΠ°Ρ ΠΊΠΎΡΠΎΡΠΎΠΉ ΠΏΠΎΠ·Π²ΠΎΠ»ΡΠ΅Ρ ΠΏΠΎΡΡΡΠΎΠΈΡΡ ΠΌΠΎΠ΄Π΅Π»Ρ ΠΎΠ±ΡΠ΅ΠΊΡΠ°, ΠΎΡΠ½ΠΎΠ²ΡΠ²Π°ΡΡΡ Π½Π° Π½Π΅ΡΠ΅ΡΠΊΠΈΡ
ΡΠ°ΡΡΡΠΆΠ΄Π΅Π½ΠΈΡΡ
ΠΈ ΠΏΡΠ°Π²ΠΈΠ»Π°Ρ
. ΠΠ°ΠΆΠ½Π΅ΠΉΡΠ΅Π΅ ΡΡΠ»ΠΎΠ²ΠΈΠ΅ ΡΠΎΠ·Π΄Π°Π½ΠΈΡ ΡΠ°ΠΊΠΎΠΉ ΠΌΠΎΠ΄Π΅Π»ΠΈ Π·Π°ΠΊΠ»ΡΡΠ°Π΅ΡΡΡ Π² ΡΠΎΠΌ, ΡΡΠΎΠ±Ρ ΠΏΠ΅ΡΠ΅Π²Π΅ΡΡΠΈ Π½Π΅ΡΠ΅ΡΠΊΠΈΠ΅, ΠΊΠ°ΡΠ΅ΡΡΠ²Π΅Π½Π½ΡΠ΅ ΠΎΡΠ΅Π½ΠΊΠΈ, ΠΏΡΠΈΠΌΠ΅Π½ΡΠ΅ΠΌΡΠ΅ ΡΠ΅Π»ΠΎΠ²Π΅ΠΊΠΎΠΌ, Π½Π° ΡΠ·ΡΠΊ ΠΌΠ°ΡΠ΅ΠΌΠ°ΡΠΈΠΊΠΈ, ΠΊΠΎΡΠΎΡΠ°Ρ Π±ΡΠ΄Π΅Ρ ΠΏΠΎΠ½ΡΡΠ½Π° Π²ΡΡΠΈΡΠ»ΠΈΡΠ΅Π»ΡΠ½ΠΎΠΉ ΠΌΠ°ΡΠΈΠ½Π΅. ΠΠ°ΠΈΠ±ΠΎΠ»Π΅Π΅ ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΠ΅ΠΌΡΠΌΠΈ ΡΠ²Π»ΡΡΡΡΡ Π½Π΅ΡΠ΅ΡΠΊΠΈΠ΅ Π²ΡΠ²ΠΎΠ΄Ρ Ρ ΠΏΠΎΠΌΠΎΡΡΡ ΡΠΏΠΎΡΠΎΠ±ΠΎΠ² ΠΠ°ΠΌΠ΄Π°Π½ΠΈ ΠΈ Π‘ΡΠ³Π΅Π½ΠΎ. Π Π½Π΅ΡΠ΅ΡΠΊΠΎΠΌ Π²ΡΠ²ΠΎΠ΄Π΅ ΡΠΈΠΏΠ° ΠΠ°ΠΌΠ΄Π°Π½ΠΈ Π·Π½Π°ΡΠ΅Π½ΠΈΠ΅ Π²ΡΡ
ΠΎΠ΄Π½ΠΎΠΉ ΠΏΠ΅ΡΠ΅ΠΌΠ΅Π½Π½ΠΎΠΉ Π·Π°Π΄Π°ΡΡΡΡ Π½Π΅ΡΠ΅ΡΠΊΠΈΠΌΠΈ ΡΠ΅ΡΠΌΠ°ΠΌΠΈ, Π² Π·Π°ΠΊΠ»ΡΡΠ΅Π½ΠΈΠΈ ΡΠΈΠΏΠ° Π‘ΡΠ³Π΅Π½ΠΎ β ΠΊΠ°ΠΊ Π»ΠΈΠ½Π΅ΠΉΠ½Π°Ρ ΠΊΠΎΠΌΠ±ΠΈΠ½Π°ΡΠΈΡ Π²Ρ
ΠΎΠ΄Π½ΡΡ
ΠΏΠ΅ΡΠ΅ΠΌΠ΅Π½Π½ΡΡ
. ΠΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ Π² ΠΎΠ±Π»Π°ΡΡΠΈ ΠΏΡΠΈΠΌΠ΅Π½Π΅Π½ΠΈΡ Π½Π΅ΡΠ΅ΡΠΊΠΎΠΉ Π»ΠΎΠ³ΠΈΠΊΠΈ Π² ΡΠΎΡΠΈΠΎΡΠΊΠΎΠ½ΠΎΠΌΠΈΡΠ΅ΡΠΊΠΈΡ
ΡΠΈΡΡΠ΅ΠΌΠ°Ρ
ΠΏΠΎΠ·Π²ΠΎΠ»ΡΡΡ Π³ΠΎΠ²ΠΎΡΠΈΡΡ ΠΎ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΠΈ Π΅Π΅ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΡ Π΄Π»Ρ ΠΎΡΠ΅Π½ΠΊΠΈ ΠΊΠΎΠΌΠΏΠ΅ΡΠ΅Π½ΡΠΈΠΉ ΡΡΡΠ΄Π΅Π½ΡΠΎΠ² Π²ΡΠ·ΠΎΠ²
Longitudinal Hadronic Shower Development in a Combined Calorimeter
This work is devoted to the experimental study of the longitudinal hadronic
shower development in the ATLAS barrel combined prototype calorimeter
consisting of the lead-liquid argon electromagnetic part and the
iron-scintillator hadronic part. The results have been obtained on the basis of
the 1996 combined test beam data which have been taken on the H8 beam of the
CERN SPS, with the pion beams of 10, 20, 40, 50, 80, 100, 150 and 300 GeV/c.
The degree of description of generally accepted Bock parameterization of the
longitudinal shower development has been investigated. It is shown that this
parameterization does not give satisfactory description for this combined
calorimeter. Some modification of this parameterization, in which the e/h
ratios of the compartments of the combined calorimeter are used, is suggested
and compared with the experimental data. The agreement between such
parameterization and the experimental data is demonstrated.Comment: Latex, 21 pages, 10 figure
Non-compensation of an Electromagnetic Compartment of a Combined Calorimeter
The method of extraction of the ratio, the degree of non-compensation,
of the electromagnetic compartment of the combined calorimeter is suggested.
The ratio of has been determined on the basis of the 1996
combined calorimeter test beam data. This value agrees with the prediction that
for this electromagnetic calorimeter.Comment: LATEX, 17 pages, 7 figure
Non-perturbative proton stability
Proton decay is a generic prediction of GUT models and is therefore an
important channel to detect the existence of unification or to set limits on
GUT models. Current bounds on the proton lifetime are around 10^33 years, which
sets stringent limits on the GUT scale. These limits are obtained under
`reasonable' assumptions about the size of the hadronic matrix elements. In
this paper we present a non-perturbative calculation of the hadronic matrix
elements within the chiral bag model of the proton. We argue that there is an
exponential suppression of the matrix elements, due to non-perturbative QCD,
that stifles proton decay by orders of magnitude -- potentially O(10^-10). This
suppression is present for small quark masses and is due to the chiral symmetry
breaking of QCD. Such a suppression has clear implications for GUT models and
could resuscitate several scenarios
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