117 research outputs found

    The theory of heterogeneous dielectric nanostructures with non-typical low-threshold nonlinearity

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    AbstractThe recently discovered, ultralow-threshold, nonlinear refraction of low-intensity laser radiation in dielectric nanostructures has an atypical dependence on radiation intensity in the pulsed and continuous modes. In this study, we present a theoretical explanation. The theory suggests that the nonlinearity is photoinduced in nature, rather than thermal, and depends directly on the nanoparticle electronic structure and the relationship between permittivities of the dielectric matrix and the nanoparticles

    Green’s Function Method for Electromagnetic and Acoustic Fields in Arbitrarily Inhomogeneous Media

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    An analytical method based on the Green’s function for describing the electromagnetic field, scalar-vector and phase characteristics of the acoustic field in a stationary isotropic and arbitrarily inhomogeneous medium is proposed. The method uses, in the case of an electromagnetic field, the wave equation proposed by the author for the electric vector of the electromagnetic field, which is valid for dielectric and magnetic inhomogeneous media with conductivity. In the case of an acoustic field, the author uses the wave equation proposed by the author for the particle velocity vector and the well-known equation for acoustic pressure in an inhomogeneous stationary medium. The approach used allows one to reduce the problem of solving differential wave equations in an arbitrarily inhomogeneous medium to the problem of taking an integral

    Les droits disciplinaires des fonctions publiques : « unification », « harmonisation » ou « distanciation ». A propos de la loi du 26 avril 2016 relative à la déontologie et aux droits et obligations des fonctionnaires

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    The production of tt‟ , W+bb‟ and W+cc‟ is studied in the forward region of proton–proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98±0.02 fb−1 . The W bosons are reconstructed in the decays W→ℓΜ , where ℓ denotes muon or electron, while the b and c quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions.The production of tt‟t\overline{t}, W+bb‟W+b\overline{b} and W+cc‟W+c\overline{c} is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 ±\pm 0.02 \mbox{fb}^{-1}. The WW bosons are reconstructed in the decays W→ℓΜW\rightarrow\ell\nu, where ℓ\ell denotes muon or electron, while the bb and cc quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions

    Measurement of the J/ψ pair production cross-section in pp collisions at s=13 \sqrt{s}=13 TeV

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    The production cross-section of J/ψ pairs is measured using a data sample of pp collisions collected by the LHCb experiment at a centre-of-mass energy of s=13 \sqrt{s}=13 TeV, corresponding to an integrated luminosity of 279 ±11 pb−1^{−1}. The measurement is performed for J/ψ mesons with a transverse momentum of less than 10 GeV/c in the rapidity range 2.0 < y < 4.5. The production cross-section is measured to be 15.2 ± 1.0 ± 0.9 nb. The first uncertainty is statistical, and the second is systematic. The differential cross-sections as functions of several kinematic variables of the J/ψ pair are measured and compared to theoretical predictions.The production cross-section of J/ψJ/\psi pairs is measured using a data sample of pppp collisions collected by the LHCb experiment at a centre-of-mass energy of s=13 TeV\sqrt{s} = 13 \,{\mathrm{TeV}}, corresponding to an integrated luminosity of 279±11 pb−1279 \pm 11 \,{\mathrm{pb^{-1}}}. The measurement is performed for J/ψJ/\psi mesons with a transverse momentum of less than 10 GeV/c10 \,{\mathrm{GeV}}/c in the rapidity range 2.0<y<4.52.0<y<4.5. The production cross-section is measured to be 15.2±1.0±0.9 nb15.2 \pm 1.0 \pm 0.9 \,{\mathrm{nb}}. The first uncertainty is statistical, and the second is systematic. The differential cross-sections as functions of several kinematic variables of the J/ψJ/\psi pair are measured and compared to theoretical predictions

    Measurement of forward W→eÎœW\to e\nu production in pppp collisions at s=8 \sqrt{s}=8\,TeV

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    A measurement of the cross-section for W→eÎœW \to e\nu production in pppp collisions is presented using data corresponding to an integrated luminosity of 2 2\,fb−1^{-1} collected by the LHCb experiment at a centre-of-mass energy of s=8 \sqrt{s}=8\,TeV. The electrons are required to have more than 20 20\,GeV of transverse momentum and to lie between 2.00 and 4.25 in pseudorapidity. The inclusive WW production cross-sections, where the WW decays to eÎœe\nu, are measured to be \begin{align*} \begin{split} \sigma_{W^{+} \to e^{+}\nu_{e}}&=1124.4\pm 2.1\pm 21.5\pm 11.2\pm 13.0\,\mathrm{pb},\\ \sigma_{W^{-} \to e^{-}\bar{\nu}_{e}}&=\,\,\,809.0\pm 1.9\pm 18.1\pm\,\,\,7.0\pm \phantom{0}9.4\,\mathrm{pb}, \end{split} \end{align*} where the first uncertainties are statistical, the second are systematic, the third are due to the knowledge of the LHC beam energy and the fourth are due to the luminosity determination. Differential cross-sections as a function of the electron pseudorapidity are measured. The W+/W−W^{+}/W^{-} cross-section ratio and production charge asymmetry are also reported. Results are compared with theoretical predictions at next-to-next-to-leading order in perturbative quantum chromodynamics. Finally, in a precise test of lepton universality, the ratio of WW boson branching fractions is determined to be \begin{align*} \begin{split} \mathcal{B}(W \to e\nu)/\mathcal{B}(W \to \mu\nu)=1.020\pm 0.002\pm 0.019, \end{split} \end{align*} where the first uncertainty is statistical and the second is systematic.A measurement of the cross-section for W→eÎœW \to e\nu production in pppp collisions is presented using data corresponding to an integrated luminosity of 2 2\,fb−1^{-1} collected by the LHCb experiment at a centre-of-mass energy of s=8 \sqrt{s}=8\,TeV. The electrons are required to have more than 20 20\,GeV of transverse momentum and to lie between 2.00 and 4.25 in pseudorapidity. The inclusive WW production cross-sections, where the WW decays to eÎœe\nu, are measured to be \begin{equation*} \sigma_{W^{+} \to e^{+}\nu_{e}}=1124.4\pm 2.1\pm 21.5\pm 11.2\pm 13.0\,\mathrm{pb}, \end{equation*} \begin{equation*} \sigma_{W^{-} \to e^{-}\bar{\nu}_{e}}=\,\,\,809.0\pm 1.9\pm 18.1\pm\,\,\,7.0\pm \phantom{0}9.4\,\mathrm{pb}, \end{equation*} where the first uncertainties are statistical, the second are systematic, the third are due to the knowledge of the LHC beam energy and the fourth are due to the luminosity determination. Differential cross-sections as a function of the electron pseudorapidity are measured. The W+/W−W^{+}/W^{-} cross-section ratio and production charge asymmetry are also reported. Results are compared with theoretical predictions at next-to-next-to-leading order in perturbative quantum chromodynamics. Finally, in a precise test of lepton universality, the ratio of WW boson branching fractions is determined to be \begin{equation*} \mathcal{B}(W \to e\nu)/\mathcal{B}(W \to \mu\nu)=1.020\pm 0.002\pm 0.019, \end{equation*} where the first uncertainty is statistical and the second is systematic.A measurement of the cross-section for W → eÎœ production in pp collisions is presented using data corresponding to an integrated luminosity of 2 fb−1^{−1} collected by the LHCb experiment at a centre-of-mass energy of s=8 \sqrt{s}=8 TeV. The electrons are required to have more than 20 GeV of transverse momentum and to lie between 2.00 and 4.25 in pseudorapidity. The inclusive W production cross-sections, where the W decays to eÎœ, are measured to be σW+→e+Îœe=1124.4±2.1±21.5±11.2±13.0pb, {\sigma}_{W^{+}\to {e}^{+}{\nu}_e}=1124.4\pm 2.1\pm 21.5\pm 11.2\pm 13.0\kern0.5em \mathrm{p}\mathrm{b}, σW−→e−Μ‟e=809.0±1.9±18.1±7.0±9.4 pb, {\sigma}_{W^{-}\to {e}^{-}{\overline{\nu}}_e}=809.0\pm 1.9\pm 18.1\pm \kern0.5em 7.0\pm \kern0.5em 9.4\,\mathrm{p}\mathrm{b}, where the first uncertainties are statistical, the second are systematic, the third are due to the knowledge of the LHC beam energy and the fourth are due to the luminosity determination

    Measurements of prompt charm production cross-sections in pp collisions at s=5 \sqrt{s}=5 TeV

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    Production cross-sections of prompt charm mesons are measured using data from pppp collisions at the LHC at a centre-of-mass energy of 5 5\,TeV. The data sample corresponds to an integrated luminosity of 8.60±0.33 8.60\pm0.33\,pb−1^{-1} collected by the LHCb experiment. The production cross-sections of D0D^0, D+D^+, Ds+D_s^+, and D∗+D^{*+} mesons are measured in bins of charm meson transverse momentum, pTp_{\text{T}}, and rapidity, yy. They cover the rapidity range 2.0<y<4.52.0 < y < 4.5 and transverse momentum ranges 0<pT<10 GeV/c0 < p_{\text{T}} < 10\, \text{GeV}/c for D0D^0 and D+D^+ and 1<pT<10 GeV/c1 < p_{\text{T}} < 10\, \text{GeV}/c for Ds+D_s^+ and D∗+D^{*+} mesons. The inclusive cross-sections for the four mesons, including charge-conjugate states, within the range of 1<pT<8 GeV/c1 < p_{\text{T}} < 8\, \text{GeV}/c are determined to be \begin{equation*} \sigma(pp\rightarrow D^0 X) = 1190 \pm 3 \pm 64\,\mu\text{b} \end{equation*} \begin{equation*} \sigma(pp\rightarrow D^+ X) = 456 \pm 3 \pm 34\,\mu\text{b} \end{equation*} \begin{equation*} \sigma(pp\rightarrow D_s^+ X) = 195 \pm 4 \pm 19\,\mu\text{b} \end{equation*} \begin{equation*} \sigma(pp\rightarrow D^{*+} X)= 467 \pm 6 \pm 40\,\mu\text{b} \end{equation*} where the uncertainties are statistical and systematic, respectively.Production cross-sections of prompt charm mesons are measured using data from pp collisions at the LHC at a centre-of-mass energy of 5 TeV. The data sample corresponds to an integrated luminosity of 8.60 ± 0.33 pb−1^{−1} collected by the LHCb experiment. The production cross-sections of D0^{0}, D+^{+}, Ds+_{s}^{+} , and D∗+^{∗+} mesons are measured in bins of charm meson transverse momentum, pT_{T}, and rapidity, y. They cover the rapidity range 2.0 < y < 4.5 and transverse momentum ranges 0 < pT_{T} < 10 GeV/c for D0^{0} and D+^{+} and 1 < pT_{T} < 10 GeV/c for Ds+_{s}^{+} and D∗+^{∗+} mesons. The inclusive cross-sections for the four mesons, including charge-conjugate states, within the range of 1 < pT_{T} < 8 GeV/c are determined to be σ(pp→D0X)=1004±3±54ÎŒb,σ(pp→D+X)=402±2±30ÎŒb,σ(pp→Ds+X)=170±4±16ÎŒb,σ(pp→D∗+X)=421±5±36ÎŒb, \begin{array}{l}\sigma \left( pp\to {D}^0X\right)=1004\pm 3\pm 54\mu \mathrm{b},\\ {}\sigma \left( pp\to {D}^{+}X\right)=402\pm 2\pm 30\mu \mathrm{b},\\ {}\sigma \left( pp\to {D}_s^{+}X\right)=170\pm 4\pm 16\mu \mathrm{b},\\ {}\sigma \left( pp\to {D}^{\ast +}X\right)=421\pm 5\pm 36\mu \mathrm{b},\end{array} where the uncertainties are statistical and systematic, respectively.Production cross-sections of prompt charm mesons are measured using data from pppp collisions at the LHC at a centre-of-mass energy of 5 5\,TeV. The data sample corresponds to an integrated luminosity of 8.60±0.33 8.60\pm0.33\,pb−1^{-1} collected by the LHCb experiment. The production cross-sections of D0D^0, D+D^+, Ds+D_s^+, and D∗+D^{*+} mesons are measured in bins of charm meson transverse momentum, pTp_{\text{T}}, and rapidity, yy. They cover the rapidity range 2.0<y<4.52.0<y<4.5 and transverse momentum ranges 0<pT<10 GeV/c0 < p_{\text{T}} < 10\, \text{GeV}/c for D0D^0 and D+D^+ and 1<pT<10 GeV/c1 < p_{\text{T}} < 10\, \text{GeV}/c for Ds+D_s^+ and D∗+D^{*+} mesons. The inclusive cross-sections for the four mesons, including charge-conjugate states, within the range of 1<pT<8 GeV/c1 < p_{\text{T}} < 8\, \text{GeV}/c are determined to be \sigma(pp\rightarrow D^0 X) = 1004 \pm 3 \pm 54\,\mu\text{b} \sigma(pp\rightarrow D^+ X) = 402 \pm 2 \pm 30\,\mu\text{b} \sigma(pp\rightarrow D_s^+ X) = 170 \pm 4 \pm 16\,\mu\text{b} \sigma(pp\rightarrow D^{*+} X)= 421 \pm 5 \pm 36\,\mu\text{b} where the uncertainties are statistical and systematic, respectively

    Response to comment “On the existence of excitonic signatures in the optical response of metal–organic frameworks”

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    \u3cp\u3eThis is a response to a comment on the interpretation of the origin of the nonlinear changes of optical properties of van der Waals' metal–organic frameworks (MOFs). The concerns are addressed by clarifying potential pitfalls in density functional theory (DFT) simulations, careful analysis of prior literature, and additionally discussing the previous experimental results to emphasize the applicability of the excitonic concept in molecular crystals, such as MOFs.\u3c/p\u3

    Exciton Spectroscopy of Spatially Separated Electrons and Holes in the Dielectric Quantum Dots

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    It is shown that in the potential energy of an exciton of spatially separated electrons and holes (hole moves in the amount of quantum dots (QDs), and the electron is localized on a spherical surface section (QD—dielectric matrix)) taking into account centrifugal energy gives rise band of the quasi-stationary surface exciton states that with the increase of the radius of QD becomes stationary state. The mechanisms of formation of the spectra of interband and intraband absorption (emission) of light in nanosystems containing aluminum oxide QDs, placed in the matrix of vacuum oil, are presented. It is shown that the electron transitions in the area of the surface exciton states cause significant absorption in the visible and near infrared wavelengths, and cause the experimentally observed significant blurring of the absorption edge
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