New measurements of the T20 component of tensor analyzing power in the reaction γd→ppπ− for photon energies 400−700 MeV are presented. The experiment was carried out on an internal tensor-polarized gas deuterium target of the VEPP-3 electron storage ring in 2023 with the use of tagged quasi-real photons and two-proton coincidence. For determination of T20, the asymmetry caused by a change of the sign of the tensor polarization of the deuteron target was measured. The new data are compared with the results of theoretical calculations based on the quasi-free approximation including πN and NN rescattering effects.

Benzene is one of the most common classes of industrial chemicals. As a rule, it enters the atmosphere as a result of man-made accidents and during the evaporation of solvents. Benzene and its derivatives are toxic and have a negative impact on the environment and the human body. Therefore, issues related to the transformation of benzene in the atmosphere are of increased interest. In this study, the structures and electronic energies of equilibrium configurations and transition complexes of the C6H6F and C6H6F+ systems are calculated using the density functional theory. It is shown that the interaction of benzene with atomic fluorine can proceed through two channels: the elimination of hydrogen with the formation of a phenyl radical and the addition of a fluorine atom with the formation of an ipso-fluorocyclohexadienyl radical. It is established that for the dissociation of the ipso-fluorocyclohexadienyl radical into fluorobenzene and atomic hydrogen, it is necessary to expend about 27 kcal/mol. This indicates a low probability of this process occurring at low temperatures. Under experimental conditions, when the temperature of fluorine atoms is about 1000 K, the ipso-fluorocyclohexadienyl radical decomposes to form fluorobenzene. In this case, the occurrence of secondary reactions is unlikely. The conclusions drawn from the analysis of the results of quantum chemical calculations are in close agreement with the experimental data.

Benzene and its derivatives are extremely important substances in modern chemical technologies. However, emissions of these substances have an extremely negative impact on the atmosphere and ecology. Benzene is a substance of the second class of danger and its effect on the human body is fraught with serious consequences. In the event of man-made disasters, it is an urgent task to convert benzene into less toxic substances. In this study, using a low-pressure flow reactor, the kinetic patterns of the reactions of atomic fluorine with benzene, fluorobenzene, and chlorobenzene at a temperature of T = 293 K and a pressure of 0.8–1.3 Torr are established. The concentrations of reagents and products are controlled by molecular beam mass spectrometry. To determine the reaction rate constants, the method of competing reactions is used. The reaction of fluorine atoms with cyclohexane is chosen as a competitor. As a result of the analysis using the experimental and published data, the following values of the rate constants of the studied reactions are obtained.

In Budker Institute of Nuclear Physics SB RAS the magnetic elements of transfer channel for charged particle beams from SIS18 to SIS100 (FAIR, Germany) [1] were developed. The article presents a description of the quadrupole magnet Q2 and serial magnetic measurements results. Magnetic measurements with application of rotating harmonic coil and moving carriage with linear array of Hall sensors were taken. Quadrupole lenses provide magnetic field integral gradient with high quality (<5·10-3) and satisfy the requirements. High order harmonics are present in the magnetic field due to manufacturing and assembly errors and can imperfect on beam dynamics. Main attention was considered to the third (sextupole) harmonic amplitude, determinate the chromatic properties of the lens. It allows select manufactured magnets to distortion value and minimize imperfection of beam dynamics by optimal theirs arrangement.

— The review presents the experiments performed with the KEDR detector at the e^ + e^ - collider VEPP-4M in the energy range of √(s) = 1.84–3.88 GeV. The cross section of e^ + e^ - annihilation to hadrons was measured at 22 points of this range and the search for narrow resonances was conducted below 3.1 GeV. The masses of J / . -0emψ and ψ (2S) mesons were measured with a record accuracy better than 3 ×10^ - 6 ; their partial and total widths were determined. Measurements of the tau lepton mass and masses of charged and neutral D mesons were performed with high precision. The measurements of the ψ (3770) parameters are discussed, and attention is drawn to some inconsistency of the procedure employed by the Particle Data Group for determining its parameters.

We present the study of the decay J/ψ → ρπ . The results are based on of 5.2 million J/ψ events collected by the KEDR detector at the VEPP-4M collider. The branching fractions are measured to be ℬ ( J/ψ → ρπ ) = (2 . 072 ± 0 . 017 ± 0 . 062) ∙ 10 − 2 and ℬ ( J/ψ → π + π − π 0 ) = (1 . 878 ± 0 . 013 ± 0 . 051) ∙ 10 − 2 , where the first uncertainties are statistical and the second systematic. Our results are more precise than the previous relative measurements.

Halogenated acids are of anthropogenic and natural origin and play an important role in atmospheric processes. The global distribution and high stability of halogenated acids is concerning because they are toxic, accumulate in surface waters, and pose a threat to humans and the ecosystem. Knowledge of the reaction mechanism of halogenated acids in the gas phase makes it possible to explain and control many important processes occurring in the atmosphere and during combustion. In this paper, we experimentally study the reactions of atomic fluorine with monochloroacetic, dichloroacetic, trichloroacetic, trifluoroacetic, and pentafluoropropionic acids at a pressure of 1 Torr. The experiments are carried out using a flow reactor connected to a mass spectrometer with a modulated beam. The rate constants of these reactions at room temperature are determined by the method of competing reactions (MCR) using the available published data. It is shown that in this series the fastest reaction is F + CH 2 ClCOOH. In addition, the temperature dependences of the rate constants are obtained for F + CF 3 COOH and F + C 2 F 5 COOH reactions in the ranges of 258–343 and 262–343 K, respectively.

Using a low-pressure flow reactor, the kinetic regularities of the reaction of atomic fluorine with monochloroacetic acid at temperature T = 293 K are studied. The concentrations of the reagents are monitored by molecular beam mass spectrometry, detecting the molecular peaks of the substances. Using the published data, the value of the reaction rate constant $$k = (9.6 \pm 3.8) \times {{10}^{{ - 11}}}$$ cm3 molecules–1 s–1, which is the average value determined by comparison with the rate constants of competing reactions (kref), is calculated. The ratios of the rate constants k/kref, equal to 0.99 ± 0.12 and 0.75 ± 0.04, respectively, are determined for two competing reactions: a fluorine atom with 2-fluoroethanol and a fluorine atom with cyclohexane. The rate constants of the reaction of atomic fluorine with monochloroacetic acid are compared with the rate constants of reactions of atomic fluorine with chlorine-substituted acetic acids: dichloroacetic and trichloroacetic acids.

Using the 1.32 pb^-1 statistics collected at the J/ψ peak with the KEDR detector at the VEPP-4M e^+e^- collider, we measured the branching fractions of J/ψ meson decays to the final states 2( π ^+π ^-)π ^0 , K^+K^-π ^+π ^-π ^0 , 2( π ^+π ^-) and K^+K^-π ^+π ^- . The results obtained for the decays J/ψ→ 2( π ^+π ^-)π ^0 , J/ψ→ K^+K^-π ^+π ^-π ^0 contradict the measurements performed by other groups in the last century, but agree well with recent results of BABAR and BESIII collaborations.

Abstract Using the 1.32 $$\hbox {pb}^{-1}$$ pb - 1 statistics collected at the $$J/\psi $$ J / ψ peak with the KEDR detector at the VEPP-4M $$e^{+}e^{-\, }$$ e + e - collider, we measured the branching fractions of $$J/\psi $$ J / ψ meson decays to the final states 2( $$\pi ^{+}\pi ^{-})\pi ^{0}$$ π + π - ) π 0 , $$K^{+}K^{-}\pi ^{+}\pi ^{-}\pi ^{0}$$ K + K - π + π - π 0 , 2( $$\pi ^{+}\pi ^{-})$$ π + π - ) and $$K^{+}K^{-}\pi ^{+}\pi ^{-}$$ K + K - π + π - . The results obtained for the decays $$J/\psi \rightarrow $$ J / ψ → 2( $$\pi ^{+}\pi ^{-})\pi ^{0}$$ π + π - ) π 0 , $$J/\psi \rightarrow K^{+}K^{-}\pi ^{+}\pi ^{-}\pi ^{0}$$ J / ψ → K + K - π + π - π 0 contradict the measurements performed by other groups in the last century, but agree well with recent results of BABAR and BESIII collaborations.

Benzyl and hydroxyethyl radicals play an important role in the combustion and oxidation of toluene and ethanol. As a result of their reactions with nitrogen oxides, a number of toxicants are formed, including soot particles. Establishing the mechanism of reactions of benzyl and hydroxyethyl radicals with nitrogen oxides will make it possible to explain many important chemical processes during combustion and in the atmosphere. In this work, using an experimental technique with a flow reactor and a time-of-flight mass spectrometer operating in the multiphoton ionization mode, we study the reactions of benzyl and hydroxyethyl radicals with nitric oxide in the temperature range of 253–353 K at a pressure of 1 mbar. Multiphoton dissociation spectra of hydroxyethyl radicals are obtained for different types of dyes from a tunable laser in the laser radiation wavelength range from 425 to 590 nm. The form of the temperature dependence of the ratio of the rate constants of the reactions of nitric oxide with benzyl and hydroxyethyl radicals has been experimentally established. Using the literature data by the method of competing reactions, the value of the rate constant of the reaction NO with C6H5CH2 at a temperature T = 299 K is found.

Using the 1.32 pb(-1) statistics collected at the J/psi peak with the KEDR detector at the VEPP-4M e(+)e(-) collider, we measured the branching fractions of J/psi meson decays to the final states 2(pi(+)pi(-))pi(0), K+K- pi(+)pi(-)pi(0), 2(pi(+)pi(-)) and K+K- pi(+)pi(-). The results obtained for the decays J/psi -> 2(pi(+)pi(-))pi(0), J/psi -> K+K- pi(+)pi(-)pi(0) contradict the measurements performed by other groups in the last century, but agree well with recent results of BABAR and BESIII collaborations.

Using the 1.32 pb^-1 statistics collected at the J/ψ peak with the KEDR detector at the VEPP-4M e^+e^- collider, we measured the branching fractions of J/ψ meson decays to the final states 2( π ^+π ^-)π ^0 , K^+K^-π ^+π ^-π ^0 , 2( π ^+π ^-) and K^+K^-π ^+π ^- . The results obtained for the decays J/ψ→ 2( π ^+π ^-)π ^0 , J/ψ→ K^+K^-π ^+π ^-π ^0 contradict the measurements performed by other groups in the last century, but agree well with recent results of BABAR and BESIII collaborations.

We review the recent results obtained by the KEDR experiment in the charmonium energy range. They include the measurements of J/psi meson total and partial widths and exclusive branching fractions, study of D+ and D-0 meson masses and R between 1.8 and 7.0 GeV.

The mass spectra of negative ions of aqueous solutions of completely neutralized monochloroacetic acid (MCA), dichloroacetic acid (DCA), and trichloroacetic acid (TCA) with a concentration of 0.01 mol/L at 20°C are obtained by the mass spectrographic method of electrospraying electrolyte solutions in vacuum. In all the distributions according to the degree of hydration of the acid residue, the dependence of the ion current intensity on the number of water molecules in the ion current is found. At an acid concentration of 0.01 mol/L, the number of hydrated monochloroacetic and dichloroacetic ions decreases monotonically with the increasing degree of hydration. For a TCA solution, the ion current intensity reaches the maximum of the distribution for two water molecules in the ion.

The measurements of Montenbrook et al. to determine the water surface level of the Walchensee alpine lake in Bavaria (Germany) are a vivid example of the manifestation of the peculiarities of the relationship between the GPS satellite system as a source and remote sensing of the Earth’s surface. The experiments were conducted in 2007 in the framework the GORS (GPS Occultation, Reflectometry and Scatterometry) program. The authors described the observed features in detail but did not provide their physical justification. In this study, it is shown that the observed effects are caused by the resonant interaction of electromagnetic waves with a medium containing Rydberg molecular complexes. They are the main reason for the delay of satellite constellation signals at altitudes of 60 to 110 km.

The increase in the concentration of methane in the atmosphere as a result of anthropogenic activity, melting of permafrost, and decomposition of gas hydrates on the seabed has attracted close attention of the scientific community in recent decades due to the potentially dangerous effect of methane on the ozone layer and the Earth’s climate. According to various estimates, the greenhouse effect from methane is dozens of times stronger than the similar effect from carbon dioxide; therefore, the processes of methane transfer to the upper layers of the Earth’s atmosphere, as well as its lifetime and interaction with other substances present in the stratosphere, mesosphere and ionosphere are of great scientific interest. In this study, we consider the chemical reactions occurring during collisions of methane molecules with methyl carbonyl oxide CH3CHOO in the upper atmosphere. It is shown that this process initiates the formation of the OH radical and starts a cascade of chemical reactions, the products of which are CH3, atomic hydrogen, acetone, acetaldehyde, propaldehyde, methyl alcohol, and water. These compounds are able to actively influence the composition of the atmosphere and its physicochemical properties.