123 research outputs found
Thermophysical characteristics of radioactive graphite - Water vapor system
The article considers thermophysical characteristics of radioactive graphite - water vapor system in temperature range 373-3273K. The research was made by thermodynamic modeling method using TERRA software. We determined 4 temperature intervals in which changes of thermophysical characteristics of radioactive graphite - water vapor system occur. © 2017 The Authors, published by EDP Sciences
Electromagnetic Pion Form Factor and Neutral Pion Decay Width
The electromagnetic pion form factor, , is calculated for
spacelike- in impulse approximation using a confining quark propagator,
, and a dressed quark-photon vertex, , obtained from realistic,
nonperturbative Dyson-Schwinger equation studies. Good agreement with the
available data is obtained for and other pion observables,
including the decay . This calculation
suggests that soft, nonperturbative contributions dominate at
presently accessible~.Comment: 25 pages, LaTeX, elsart.sty, 5 figures, To appear in Nucl. Phys.
Magnetooptical Study of Zeeman Effect in Mn modulation-doped InAs/InGaAs/InAlAs Quantum Well Structures
We report on a magneto-photoluminescence (PL) study of Mn modulation-doped
InAs/InGaAs/InAlAs quantum wells. Two PL lines corresponding to the radiative
recombination of photoelectrons with free and bound-on-Mn holes have been
observed. In the presence of a magnetic field applied in the Faraday geometry
both lines split into two circularly polarized components. While temperature
and magnetic field dependences of the splitting are well described by the
Brillouin function, providing an evidence for exchange interaction with spin
polarized manganese ions, the value of the splitting exceeds the expected value
of the giant Zeeman splitting by two orders of magnitude for a given Mn
density. Possible reasons of this striking observation are discussed
Chiral Anomaly and
Measurement of the process has revealed a possible conflict
with what should be a solid prediction generated by the chiral anomaly. We show
that inclusion of appropirate energy-momentum dependence in the matrix element
reduces the discrepancy.Comment: 8 page standard Latex fil
Semileptonic decays in relativistic quark model
Quark model results for the decays are analysed, making use
of the dispersion formulation of the model: The form factors at are
expressed as relativistic invariant double spectral representation over
invariant masses of the initial and final mesons through their light--cone wave
functions. The dependence of the results on the quark model parameters is
studied. For various versions of the quark model the ranges , , and
are found. The effects of the constituent quark
transition form factor are briefly discussed.Comment: latex, 8 pages, 2 figure
Radiative Tau Decays with One Pseudoscalar Meson
We have calculated the decay . We present
the photon energy spectrum, the meson-photon invariant mass spectrum and the
integrated rate as a function of a photon energy cut or an invariant mass cut.
Both the internal bremsstrahlung and the structure dependent radiation have
been taken into account. To this aim we have parametrized the form factors
and , which determine the structure dependent radiation. Observables
especially suited for the measurement of the structure dependent form factors
are found and implications on the width of the discussed.Comment: p.20, TTP93-1, LaTe
Spin-polarized electric currents in diluted magnetic semiconductor heterostructures induced by terahertz and microwave radiation
We report on the study of spin-polarized electric currents in diluted
magnetic semiconductor (DMS) quantum wells subjected to an in-plane external
magnetic field and illuminated by microwave or terahertz radiation. The effect
is studied in (Cd,Mn)Te/(Cd,Mg)Te quantum wells (QWs) and (In,Ga)As/InAlAs:Mn
QWs belonging to the well known II-VI and III-V DMS material systems, as well
as, in heterovalent AlSb/InAs/(Zn,Mn)Te QWs which represent a promising
combination of II-VI and III-V semiconductors. Experimental data and developed
theory demonstrate that the photocurrent originates from a spin-dependent
scattering of free carriers by static defects or phonons in the Drude
absorption of radiation and subsequent relaxation of carriers. We show that in
DMS structures the efficiency of the current generation is drastically enhanced
compared to non-magnetic semiconductors. The enhancement is caused by the
exchange interaction of carrier spins with localized spins of magnetic ions
resulting, on the one hand, in the giant Zeeman spin-splitting, and, on the
other hand, in the spin-dependent carrier scattering by localized Mn2+ ions
polarized by an external magnetic field.Comment: 14 pages, 13 figure
Thermal characteristics of the radioactive graphite-CuO-Na2CO3-K2CO3-NaCl-KCl system in argon atmosphere
The article considers thermal characteristics of the radioactive graphite-CuO-Na2CO3-K2CO3-NaCl-KCl system in argon atmosphere. Thermodynamic calculations were carried out in the Terra program. Four temperature ranges with changes of thermal characteristics of the radioactive graphite-CuO-Na2CO3-K2CO3-NaCl-KCl system in argon atmosphere have been determined. © Published under licence by IOP Publishing Ltd
The behavior of radioactive metals (Am, Eu, Sr) during the processing of radioactive graphite in salt melts
The behavior of Am, Eu, Sr radionuclides was investigated by thermodynamic modeling method at heating of radioactive graphite in NaCl - KCl - Na2CO3 - K2CO3 molten salt with additives of nickel oxide NiO. The integrated thermodynamic analysis was carried out by means of TERRA software in temperature range 373-3273 K to determine possible composition of condensed and gaseous phases. It was established that americium is in gaseous state in temperature range 2773-3273 K. Europium is in the forms of gaseous EuO and Eu in temperature range 2373-3273 K. Strontium is in the forms of gaseous SrCl2, SrCl, Sr, SrO in temperature range 2373-3273 K. © Published under licence by IOP Publishing Ltd
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