Radiative corrections for pion and kaon production at e+e−e^+e^- colliders of energies below 2 GeV

Processes of electron-positron annihilation into charged pions and kaons are considered. Radiative corrections are taken into account exactly in the first order and within the leading logarithmic approximation in higher orders. A combined approach for accounting exact calculations and electron structure functions is used. An accuracy of the calculation can be estimated about 0.2%.Comment: 16 pages, LaTeX, epsfig.sty, 3 PostScript figure

Mini-Proceedings of the 15th meeting of the Working Group on Rad. Corrections and MC Generators for Low Energies

The mini-proceedings of the 15th Meeting of the "Working Group on Rad. Corrections and MC Generators for Low Energies" held in Mainz on April 11, 2014, are presented. These meetings, started in 2006, have as aim to bring together experimentalists and theorists working in the fields of meson transition form factors, hadronic contributions to $(g-2)_\mu$ and the effective fine structure constant, and development of Monte Carlo generators and Radiative Corrections for precision e+e- and tau physics.Comment: 21 pages, 7 contributions. Editors: S. E. Mueller and G. Venanzon

Large angle QED processes at e^+e^- colliders at energies below 3 GeV

QED processes at electron-positron colliders are considerd. We present differential cross-sections for large-angle Bhabha scattering, annihilation into muons and photons. Radiative corrections in the first order are taken into account exactly. Leading logarithmic contributions are calculated in all orders by means of the structure-function method. An accuracy of the calculation can be estimated about 0.2%.Comment: 24 pages, LaTeX, 2 PS figures, numerical results for large-angle Bhabha are adde

Influence of nanoparticles and metal vapors on the color of laboratory and atmospheric discharges

Currently, electrical discharges occurring at altitudes of tens to hundreds of kilometers from the Earth’s surface attract considerable attention from researchers from all over the world. A significant number of (nano)particles coming from outer space burn up at these altitudes. As a result, vapors of various substances, including metals, are formed at different altitudes. This paper deals with the influence of vapors and particles released from metal electrodes on the color and shape of pulse-periodic discharge in air, nitrogen, argon, and hydrogen. It presents the results of experimental studies. The discharge was implemented under an inhomogeneous electric field and was accompanied by the generation of runaway electrons and the formation of mini-jets. It was established that regardless of the voltage pulse polarity, the electrode material significantly affects the color of spherical- and cylindrical-shaped mini jets formed when bright spots appear on electrodes. Similar jets are observed when the discharge is transformed into a spark. It was shown that the color of the plasma of mini-jets is similar to that of atmospheric discharges (red sprites, blue jets, and ghosts) at altitudes of dozens of kilometers and differs from the color of plasma of pulsed diffuse discharges in air and nitrogen at the same pressure. It was revealed that to observe the red, blue and green mini-jets, it is necessary to use aluminum, iron, and copper electrodes, respectivel

Applied optical properties of diamond

In our paper we report about the optical properties of diamonds having applied sense. Radiation destruction manifests itself in the form of absorption bands and luminescence of vacancies and interstitials. The charge state of the NV centers depends on the impurity-defective composition of the sample. Accelerated particles lose their energy to Cherenkov radiation. The fine splitting of the free exciton state affects the absorption and luminescence spectra in the recombination bands of free excitons and their condensed stat

Luminescence of crystals excited by a runaway electron beam and by excilamp radiation with a peak wavelength of 222 nm

This paper presents research data on cathodoluminescence, photoluminescence, and Cherenkov radiation at 200–800 nm excited in crystals with different refractive indices by a subnanosecond runaway electron beam and by KrCl excilamp radiation with a peak wavelength of 222 nm. The data include spectral and amplitude-time characteristics measured with a resolution of up to ∼100 ps for natural and synthetic diamonds of type IIa, sapphire, CsI, ZnS, CaF2, ZrO2, Ga2O3, CaCO3, CdS, and ZnSe. The research suggests that cathodoluminescence and photoluminescence should be accounted for in Cherenkov-type detectors of runaway electrons. The results can be useful for detecting high-energy electrons in tokamak

Generation of neutrons in a nanosecond low-pressure discharge in deuterium

The neutron yield is measured in a high-voltage Townsend discharge in deuterium with a hollow cylinder made of tungsten or steel used as a polarizing anode of electrons. A flat metallic plate covered by a layer of deuterated zirconium is applied as a grounded cathode. The highest yield of neutrons in the reaction 2H(d,n)3He, ∼1.2 × 104 neutrons per pulse, is observed in the case of the tungsten anode at a deuterium pressure on the order of 100 Pa. The pulsed neutron flux duration estimated with data obtained from a scintillation detector is roughly equal to 1.5 ns