Non-catalytic bromination of benzene: a combined computational and experimental study

The non-catalytic bromination of benzene is shown experimentally to require high 5-14M concentrations of bromine in order to proceed at ambient temperatures to form predominantly bromobenzene, along with detectable (The non-catalytic bromination of benzene is shown experimentally to require high 5-14M concentrations of bromine in order to proceed at ambient temperatures to form predominantly bromobenzene, along with detectable (The non-catalytic bromination of benzene is shown experimentally to require high 5-14M concentrations of bromine in order to proceed at ambient temperatures to form predominantly bromobenzene, along with detectable

Angular distributions in J/ψ→ppˉπ0(η)J/\psi\to p\bar{p}\pi^{0}(\eta) decays

The differential decay rates of the processes $J/\psi\to p\bar{p}\pi^{0}$ and $J/\psi\to p\bar{p}\eta$ close to the $p\bar{p}$ threshold are calculated with the help of the $N\bar{N}$ optical potential. The same calculations are made for the decays of $\psi(2S)$. We use the potential which has been suggested to fit the cross sections of $N\bar{N}$ scattering together with $N\bar{N}$ and six pion production in $e^{+}e^{-}$ annihilation close to the $p\bar{p}$ threshold. The $p\bar{p}$ invariant mass spectra is in agreement with the available experimental data. The anisotropy of the angular distributions, which appears due to the tensor forces in the $N\bar{N}$ interaction, is predicted close to the $p\bar{p}$ threshold. This anisotropy is large enough to be investigated experimentally. Such measurements would allow one to check the accuracy of the model of $N\bar{N}$ interaction.Comment: 10 pages, 8 figure

Natural explanation of recent results on e+e−→ΛΛˉe^{+}e^{-}\to\Lambda\bar{\Lambda}

We show that the recent experimental data on the cross section of the process $e^{+}e^{-}\to\Lambda\bar{\Lambda}$ near the threshold can be perfectly explained by the final-state interaction of $\Lambda$ and $\bar{\Lambda}$. The enhancement of the cross section is related to the existence of low-energy real or virtual state in the corresponding potential. We present a simple analytical formula that fits the experimental data very well.Comment: 2 pages, 1 figur

Near-threshold resonance in e+e−→ΛcΛˉce^{+}e^{-}\rightarrow\Lambda_{c}\bar{\Lambda}_{c} process

We discuss the influence of various contributions of the $\Lambda_{c}\bar{\Lambda}_{c}$ potential on the energy dependence of the cross section $e^{+}e^{-}\rightarrow\Lambda_{c}\bar{\Lambda}_{c}$ near the threshold. New BESIII experimental data on the cross section and electromagnetic form factors $G_{E}$ and $G_{M}$ are taken into account. Our predictions are in good agreement with experimental data. We predict a bound state of $\Lambda_{c}\bar{\Lambda}_{c}$ at energy $\sim 38~\textrm{MeV}$ below the threshold that may manifest itself in anomalous behavior of light meson production cross sections in a given energy region.Comment: 5 pages, 1 figur

Coupled channels and production of near-threshold B(∗)Bˉ(∗)B^{(*)}\bar{B}^{(*)} resonances in e+e−e^{+}e^{-} annihilation

The effects of final-state interaction of hadrons, produced in $e^{+}e^{-}$ annihilation near the threshold, are discussed. If there is a loosely bound state or a virtual state in a system of produced hadrons, then the energy dependence of hadroproduction cross section is very strong. Our approach is based on the use of the effective potentials accounting for the interaction between hadrons in the final state. The cases of a few channels with nonzero transition amplitudes between them are considered. It is shown that these transitions drastically change the energy dependence of the cross sections. In particular, a narrow resonance below the threshold in one channel leads to a broad peak in another channel. We explained the non-trivial energy dependence of the production cross sections of $B\bar{B}$, $B^{*}\bar{B}$, $B\bar{B}^{*}$, $B^{*}\bar{B}^{*}$ near the thresholds in $e^{+}e^{-}$ annihilation and obtained good agreement between our predictions and the experimental data available.Comment: 15 pages, 11 figure

Harmonic oscillators in the Nos\'e - Hoover thermostat

We study the dynamics of an ensemble of non-interacting harmonic oscillators in a nonlinear dissipative environment described by the Nos\'e - Hoover model. Using numerical simulation we find the histogram for total energy, which agrees with the analysis of the Nos\'e - Hoover equations effected with the method of averaging. The histogram does not correspond to Gibbs' canonical distribution. We have found oscillations at frequency proportional to $\sqrt{\alpha/m}$, $\alpha$ the dissipative parameter of thermostat and $m$ the characteristic mass of particle, about the stationary state corresponding to equilibrium. The oscillations could have an important bearing upon the analysis of simulating molecular dynamics in the Nos\'e - Hoover thermostat.Comment: 7 pages, 4 figure