64 research outputs found
Nucleon form factors in the canonically quantized Skyrme model
The explicit expressions for the electric, magnetic, axial and induced
pseudoscalar form factors of the nucleons are derived in the {\it ab initio}
quantized Skyrme model. The canonical quantization procedure ensures the
existence of stable soliton solutions with good quantum numbers. The form
factors are derived for representations of arbitrary dimension of the SU(2)
group. After fixing the two parameters of the model, and , by the
empirical mass and electric mean square radius of the proton, the calculated
electric and magnetic form factors are fairly close to the empirical ones,
whereas the the axial and induced pseudoscalar form factors fall off too slowly
with momentum transfer.Comment: 14pp including figure
In Situ Renewable Coating of Boron Carbide (B4C) for Plasma Materials for Plasma-Technological and Fusion Devices
The application of the in situ renewable protecting boron carbide (B4C) coating can prevent plasma-facing materials of plasma technology and thermonuclear devices from plasma irradiation and by this means prevents their destruction and plasma contamination by materials of their erosion. At the same time, the regimes and conditions of high adhesive deposition of B4C on tungsten and the B4C coating ability to withstand the thermal cycling and high-power density irradiation by plasma ions have not been investigated yet. The chapter considers the results of ion irradiation and thermal cycling of boron carbide coating on tungsten sample in Stand for Coating Deposition and Material Testing—CODMATT (NRNU MEPhI) and plasma irradiation during a plasma disruption in fusion device—T-10 tokamak (NRC “Kurchatov Institute”). Boron carbide coating withstands the thermal cycling and high-power density irradiation by plasma ions. It retains uniformity and adhesion to tungsten and protects it from direct plasma interaction for temperatures up to melting point of tungsten. The retaining of uniform coating in contact with tungsten substrate allows renewing the coating on its surface even after high-energy plasma loads
Neutron Thermal Cross Sections, Westcott Factors, Resonance Integrals, Maxwellian Averaged Cross Sections and Astrophysical Reaction Rates Calculated from Major Evaluated Data Libraries
We present calculations of neutron thermal cross sections, Westcott factors,
resonance integrals, Maxwellian-averaged cross sections and astrophysical
reaction rates for 843 ENDF materials using data from the major evaluated
nuclear libraries and European activation file. Extensive analysis of
newly-evaluated neutron reaction cross sections, neutron covariances, and
improvements in data processing techniques motivated us to calculate nuclear
industry and neutron physics quantities, produce s-process Maxwellian-averaged
cross sections and astrophysical reaction rates, systematically calculate
uncertainties, and provide additional insights on currently available
neutron-induced reaction data. Nuclear reaction calculations are discussed and
new results are presented.Comment: 145 pages, 15 figures, 19 table
High-Tc via electron polar coupling: relation to low-Tc superconductivity and to chiral symmetry in particle physics
Directional coupling of Thornber-Feynman polarization with the high-Tc ARPES
distribution specifies the optimum flatband pseudogap \Delta and mobile
localized quasiparticle. This coupling peaks by tuning the statistics and
interaction energy to produce stable short-ranged directional pairing that
reflects the lattice asymmetry. Analogous energy gap and BCS ratio parameters
are identified for low-Tc long-range acoustical phonons and for
quark-anti-quark tightly bound chiral pions in particle physics.Comment: 25 pages, 4 figures, accepted for publication in Physica
Electric field study with HIBP in OH and ECRH plasmas on the T-10 tokamak
The plasma potential φ and radial electric field Er were studied on T-10 in a wide range of ohmic and ECRH regimes. At densities ne> 10¹⁹ m⁻³, the potential has negative sign over the whole plasma cross section. At lower densities, the outer zone with positive φ and Er is formed. The absolute value of potential at mid-radius grows with density up to ne ≈ 3×10¹⁹ m⁻³ and then saturates. In regimes with ECR heating, |φ| decreases owing to the density pump-out and the electron temperature increase. Measurements of Er are compared with numerical simulations with several codes including nonambipolar fluxes due to the toroidal field ripple. The change of radially averaged ¬Er with density and temperature qualitatively agrees with neoclassical expectations.Потенциал плазмы φ и радиальное электрическое поле Er исследовались на токамаке T-10 в широком диапазоне омических и ЭЦР-режимов. При плотностях ne> 10¹⁹ м⁻³ потенциал имеет положительный знак во всем сечении плазмы. При меньших плотностях во внешней зоне потенциал и Er меняют знак. Абсолютное значение потенциала на середине радиуса растет с плотностью вплоть до ne ≈ 3×10¹⁹ м⁻³, а затем насыщается. В режимах с ЭЦР-нагревом абсолютная величина |φ| уменьшается за счет откачки плотности и роста электронной температуры. Измерения Er сравнивались с численными расчетами по нескольким кодам, учитывающим неамбиполярные потоки за счет гофрировки тороидального поля. Изменение среднего поля ¬Er с плотностью и температурой не противоречит неоклассическим ожиданиям.Потенціал плазми φ та радіальне електричне поле Er було досліджено на токамаці Т-10 у широкому діапазоні омічних та ЕЦР-режимів. При щiльностях ne> 10¹⁹ м⁻³ потенцiал має позитивний знак в усьому перетинi плазми. При менших щiльностях у зовнiшнiй зонi потенціал та Er змiнюють знак. Абсолютне значення потенцiалу на серединi радіуса росте зi щiльністью майже до ne ≈ 3×10¹⁹ м⁻³, а потiм насичується. У режимах з ЕЦР-нагрiвом абсолютна величина |φ|зменшується за рахунок відкачки щiльностi та росту електронноï температури. Вимiрювання Er порiвнювалися з числовими розрахунками за декiлькома кодами, які враховують неамбіполярнi потоки за рахунок гофрировки тороïдального поля. Зміна середнього поля ¬Er з щiльнiстю та температурою не протирiчить неокласичним сподiванням
Double Counting Ambiguities in the Linear Sigma Model
We study the dynamical consequences imposed on effective chiral field
theories such as the quark-level SU(2) linear model (LM) due
to the fundamental constraints of massless Goldstone pions, the normalization
of the pion decay constant and form factor, and the pion charge radius. We
discuss quark-level double counting LM ambiguities in the context of
the Salam-Weinberg compositeness condition. Then SU(3) extensions to
the kaon are briefly considered.Comment: 23 pages To be published in Journal of Physics
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