We estimated an impact of the recent CMD-3 measurement of the $e^+e^- \to
\pi^+\pi^-$ total cross section at $0.3 < \sqrt{s} < 1.2$ GeV on the leading
order hadronic contribution $a_\mu^{had,LO}$ to ...the muon anomalous magnetic
moment $a_\mu = (g_\mu-2)/2$, in presence of comparably precise ISR
measurements of the cross section by BaBar and KLOE experiments being in
significant tension with the CMD-3. Assuming that all the experiments are
affected by yet unidentified systematic effects, to account for the latter, we
scaled the experimental uncertainties following the PDG prescription, thus
facilitating a consistent joint fit of the world data on the $e^+e^- \to
\pi^+\pi^-$ total cross section. The same procedure was applied in all $e^+e^-
\to hadrons$ channels contributing to the dispersive estimate of
$a_\mu^{had,LO}$. Despite an inclusion of the new CMD-3 $\pi^+\pi^-$ data, our
estimate $a_\mu^{had,LO}(e^+e^-) = (696.2 \pm 2.9) \times 10^{-10}$ is
consistent with $a_\mu^{had,LO}(e^+e^-)$ values obtained by other authors
before publication of the CMD-3 result. Including our $a_\mu^{had,LO}$ value
into the SM prediction for $a_\mu$, we obtain $a_\mu^{SM} = (11~659~184 \pm
4_{\mathrm{tot}}) \times 10^{-10}$ which is by $4.7\sigma$ smaller than the
world average for the experimental value $a_\mu^{exp} = (11~659~205.9 \pm 2.2)
\times 10^{-10}$. We confirm the observation by the CMD-3 authors that their
$\sigma(e^+e^- \to \pi^+\pi^-)$ measurement, when taken alone, implies the
$a_\mu^{SM}$ prediction consistent with the $a_\mu^{exp}$ at $\sim 1\sigma$
level.
In order to study spontaneous attentional lapses the experimental task was used that created a moderately high attentional load and involved response choice based on stimulus feature conjunction. The ...participant's average correct response rate was 85.1%; they made errors in 9.6% trials and response omissions in 5.4% trials. Peak N1 of the evoked potential was consistent across all behavioral outcomes, while peak P2 amplitude was significantly greater before errors and response omissions compared to correct responses. The analysis of polygraphic indexes (ECG, EMG, SGR) did not reveal any arousal level reduction before attentional lapses. The proposed interpretation of the results obtained is based on the assumption that attentional lapses are mediated by the suppression of external stimuli information processing caused by the state of mind-wandering.
The Hermes experiment has investigated the tensor spin structure of the deuteron using the 27.6 GeV/c positron beam of DESY HERA. The use of a tensor-polarized deuteron gas target with only a ...negligible residual vector polarization enabled the first measurement of the tensor asymmetry A(d)zz and the tensor structure function b(d)1 for average values of the Bjorken variable 0.01< <0.45 and of the negative of the squared four-momentum transfer 0.5 GeV2 < <5 GeV2. The quantities A(d)zz and b(d)1 are found to be nonzero. The rise of b(d)1 for decreasing values of x can be interpreted to originate from the same mechanism that leads to nuclear shadowing in unpolarized scattering.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Exclusive
ρ
0
-meson electroproduction is studied by the HERMES experiment, using the 27.6 GeV longitudinally polarized electron/positron beam of HERA and a transversely polarized hydrogen target, in ...the kinematic region 1.0 GeV
2
<
Q
2
<
7.0 GeV
2
, 3.0 GeV
<
W
<
6.3 GeV, and
-
t
′
<
0.4 GeV
2
. Using an unbinned maximum-likelihood method, 25 parameters are extracted. These determine the real and imaginary parts of the ratios of several helicity amplitudes describing
ρ
0
-meson production by a virtual photon. The denominator of those ratios is the dominant amplitude, the nucleon-helicity-non-flip amplitude
F
0
1
2
0
1
2
, which describes the production of a longitudinal
ρ
0
-meson by a longitudinal virtual photon. The ratios of nucleon-helicity-non-flip amplitudes are found to be in good agreement with those from the previous HERMES analysis. The transverse target polarization allows for the first time the extraction of ratios of a number of nucleon-helicity-flip amplitudes to
F
0
1
2
0
1
2
. Results obtained in a handbag approach based on generalized parton distributions taking into account the contribution from pion exchange are found to be in good agreement with these ratios. Within the model, the data favor a positive sign for the
π
-
ρ
transition form factor. By also exploiting the longitudinal beam polarization, a total of 71
ρ
0
spin-density matrix elements is determined from the extracted 25 parameters, in contrast to only 53 elements as directly determined in earlier analyses.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Modern development of the Far East region of Russia is directly connected with elaboration and implementation of the balanced and weighed Migration Policy. Migration flows influence on various ...spheres of the state and public life. Changes of a geopolitical situation, aggravation of ethnic and other contradictions, especially in frontier areas, are capable to lead to complication in problems of national security.
The Astra testing stand and the critical assemblies simulating on this stand the special physical features of HTGRs are described. The experimental data, obtained using the Astra stand, on the ...critical parameters of assemblies with HTGR fuel pellets and an analysis of the data using the MCU computer program, which employs the Monte Carlo method, are presented taking account of the requirements of the international program on critical benchmark experiments. It is shown that the experimental data are in good agreement with the computational results.
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CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Poor dielectric properties of GaAs oxides are the drawback of the GaAs-based electronics preventing using these oxides as dielectric layers. The elemental and chemical compositions of the GaAs native ...oxide layer slightly irradiated by Ar+ ions with the fluence Q ~1 ∗ 1014 ions/cm2 have been studied by the synchrotron-based photoelectron spectroscopy. The effect of selective and total decay of arsenic oxides followed by diffusive escape of arsenic atoms from the oxide layer has been revealed. The effect results in three-fold Ga enrichment of the upper layer of the native oxide and in strong domination (~90 at%) of the Ga2O3 phase which is known to be a quite good dielectric with the bandgap width as wide as 4.8 eV. A band diagram was obtained for the native oxide nanolayer on the n-GaAs wafer. It has been shown that this natural nanostructure has a character of a p-n heterojunction.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Hard exclusive electroproduction of Formula omitted mesons is studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off a transversely ...polarized hydrogen target. The amplitudes of five azimuthal modulations of the single-spin asymmetry of the cross section with respect to the transverse proton polarization are measured. They are determined in the entire kinematic region as well as for two bins in photon virtuality and momentum transfer to the nucleon. Also, a separation of asymmetry amplitudes into longitudinal and transverse components is done. These results are compared to a phenomenological model that includes the pion pole contribution. Within this model, the data favor a positive Formula omitted transition form factor.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The subject of the research is the impact of digital technologies on the insurance market in terms of internetization, digitalization and individualization of the insurance business. The purpose of ...the research was to analyze the digital insurance concept and the process of digitalization of the insurance market based on the Russian and foreign insurers’ practices in the promotion of digital technologies, including the use of general scientific approaches and research methods. Among the results of the research were the definitions of the «digital insurance» and «digitalization of insurance activities» concepts as well as the formulation of problems and prospects for further use of digital technologies in the insurance market. The paper concludes that the introduction of new technologies in the digital economy will influence the insurance technology without changing its economic substance. Moreover, the digitalization of insurance activities will be followed by significant innovations improving the effectiveness of the former, development of new insurance programs, convergence of commercial and mutual insurance and things alike.
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