79 research outputs found
Parameters of scalar resonances from the combined analysis of data on processes and decays
A combined analysis of data on isoscalar S-wave processes
and on decays
from the DM2, Mark III and BESIII
collaborations is performed to study mesons. The method of analysis is
based on analyticity and unitarity and uses an uniformization procedure. In the
analysis limited only to the multi-channel -scattering data, two
possible sets of parameters of the were found: in both cases the
mass was about 700 MeV but the total width was either about 600 or 930 MeV. The
extension of the analysis using only the DM2 and Mark III data on the
decays does not allow to choose between these sets. However, the data from
BESIII on the di-pion mass distribution in the decay
clearly prefers the wider state. Spectroscopic implications from
results of the analysis are also discussed.Comment: the formalism is also described (text overlap) in arXiv:1108.3725;
new extended analysis of data; revised PRD versio
On CP-Odd Effects in K_L \to 2\pi and K^{\pm} \to \pi^{\pm} \pi^{\pm} \pi^{\mp} Decays Generated by Direct CP Violation
The amplitudes of the K^{\pm} \to 3\pi and K \to 2\pi decays are expressed in
terms of different combinations of one and the same set of CP-conserving and
CP-odd parameters. Extracting the magnitudes of these parameters from the data
on K \to 2\pi decays, we estimate an expected CP-odd difference between the
values of the slope parameters g^+ and g^- of the energy distributions of "odd"
pions in K^+ \to \pi^+\pi^+\pi^- and K^- \to \pi^-\pi^-\pi^+ decays.Comment: 12 pages, no figure
Perturbative framework for the pi(+)pi(-) atom
The perturbative framework is developed for the calculation of the pi(+)pi(-)
atom characteristics on the basis of the field-theoretical Bethe-Salpeter
approach. A closed expression for the first-order correction to the pi(+)pi(-)
atom lifetime has been obtained.Comment: 8 pages, LaTeX-fil
Orbital mechanism of the circular photogalvanic effect in quantum wells
It is shown that the free-carrier (Drude) absorption of circularly polarized
radiation in quantum well structures leads to an electric current flow. The
photocurrent reverses its direction upon switching the light helicity. A pure
orbital mechanism of such a circular photogalvanic effect is proposed that is
based on interference of different pathways contributing to the light
absorption. Calculation shows that the magnitude of the helicity dependent
photocurrent in -doped quantum well structures corresponds to recent
experimental observations.Comment: 5 pages, 2 figures, to be published in JETP Letter
Experimental Separation of Rashba and Dresselhaus Spin-Splittings in Semiconductor Quantum Wells
The relative strengths of Rashba and Dresselhaus terms describing the
spin-orbit coupling in semiconductor quantum well (QW) structures are extracted
from photocurrent measurements on n-type InAs QWs containing a two-dimensional
electron gas (2DEG). This novel technique makes use of the angular distribution
of the spin-galvanic effect at certain directions of spin orientation in the
plane of a QW. The ratio of the relevant Rashba and Dresselhaus coefficients
can be deduced directly from experiment and does not relay on theoretically
obtained quantities. Thus our experiments open a new way to determine the
different contributions to spin-orbit coupling
On nature of the scalar-isoscalar mesons in the uniformizing-variable method based on analyticity and unitarity
The experimental data on the processes
in the
channel have been jointly analyzed to study the status
and nature of the . The method of analysis is based on analyticity and
unitarity and uses an uniformization procedure. Some spectroscopic implications
from results of the analysis are discussed.Comment: 18 pages, 5 figures, 9 table
Spin currents in diluted magnetic semiconductors (extended version)
Spin currents resulting in the zero-bias spin separation have been observed
in unbiased diluted magnetic semiconductor structures (Cd,Mn)Te/(Cd,Mg)Te. The
pure spin current generated due to the electron gas heating by terahertz
radiation is converted into a net electric current by application of an
external magnetic field. We demonstrate that polarization of the magnetic ion
system enhances drastically the conversion due to the spin-dependent scattering
by localized Mn(2+) ions and the giant Zeeman splitting.Comment: 6 pages, 4 figure
A matrix solution to pentagon equation with anticommuting variables
We construct a solution to pentagon equation with anticommuting variables
living on two-dimensional faces of tetrahedra. In this solution, matrix
coordinates are ascribed to tetrahedron vertices. As matrix multiplication is
noncommutative, this provides a "more quantum" topological field theory than in
our previous works
PREPARATION OF VCу NANOPOWDERS OF VARIOUS PARTICAL SIZES AND COMPOSITION
Nanocrystalline powders of nonstoichiometric disordered cubic (sp. gr. Fm-3m) vanadium carbide VCy were synthesized by high-energy ball-milling and subsequent vacuum annealing. The obtained nanocrystalline powders have the particles ranging from 80 to 20 nm and different stoichiometry within its homogeneity region of VC0 6 5 to VC0 .875- The nanopowders were characterized by X-ray diffraction and scanning electron microscopy.Исследование выполнено в ИХТТ УрО РАН за счет гранта Российского научного фонда (проект № 14-23-00025)
decay within unitarized chiral perturbation theory
We improve the calculations of the decay
within the context of meson chiral lagrangians. We use a chiral unitary
approach for the meson-meson interaction, thus generating the
resonance and fixing the longstanding sign ambiguity on its contribution. This
also allows us to calculate the loops with one vector meson exchange, thus
removing a former source of uncertainty. In addition we ensure the consistency
of the approach with other processes. First, by using vector meson dominance
couplings normalized to agree with radiative vector meson decays. And, second,
by checking the consistency of the calculations with the related reaction. We find an decay width
of eV, in clear disagreement with published data but in
remarkable agreement with the most recent measurement.Comment: 15 pages, 10 figures, published versio
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