Publications by authors named "VA Nikonov"

First measurements of double-polarization observables in ω photoproduction off the proton are presented using transverse target polarization and data from the CEBAF Large Acceptance Spectrometer (CLAS) FROST experiment at Jefferson Lab. The beam-target asymmetry F has been measured using circularly polarized, tagged photons in the energy range 1200-2700 MeV, and the beam-target asymmetries H and P have been measured using linearly polarized, tagged photons in the energy range 1200-2000 MeV. These measurements significantly increase the database on polarization observables.

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Data on the reaction γp→K^{+}Λ from the CLAS experiments are used to derive the leading multipoles, E_{0+}, M_{1-}, E_{1+}, and M_{1+}, from the production threshold to 2180 MeV in 24 slices of the invariant mass. The four multipoles are determined without any constraints. The multipoles are fitted using a multichannel L+P model that allows us to search for singularities and to extract the positions of poles on the complex energy plane in an almost model-independent method.

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We report the first beam-target double-polarization asymmetries in the γ+n(p)→π^{-}+p(p) reaction spanning the nucleon resonance region from invariant mass W=1500 to 2300 MeV. Circularly polarized photons and longitudinally polarized deuterons in solid hydrogen deuteride (HD) have been used with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The exclusive final state has been extracted using three very different analyses that show excellent agreement, and these have been used to deduce the E polarization observable for an effective neutron target.

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Inhalation of fine particulate matters (PM and PM ) poses a threat for the health of population. Purpose of the study the analysis of the monitoring of fine particulate matters in the atmospheric air of Saint-Petersburg and identification of the main problems of the monitoring. Research methods methods of scientific hypothetical deductive cognition, sanitary-statistical methods, general logical methods and approaches of researches: analysis, synthesis, abstracting, generalization, induction.

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Evidence is reported for the existence of a parity doublet of Delta resonances with total angular momentum J=3/2 from photoproduction of the ppi;{0}eta final state. The two parity partners Delta(1920)P33 and Delta(1940)D33 make significant contributions to the reaction. Cascades of resonances into Delta(1232)eta, N(1535)pi, and Na0(980) are clearly observed.

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Article Synopsis
  • The CBELSA/TAPS detector measured quasifree photoproduction of eta mesons from nucleons in deuterons up to 2.5 GeV at the Bonn ELSA accelerator.
  • The experiment detected eta mesons alongside recoil protons and neutrons to compare the reactions involving neutrons and protons.
  • The results showed a significant bump in the eta production off the neutron at an energy of 1.68 GeV, which was not observed in the proton response.
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