No abstract available

[en] Photons produced by lasers or wigglers backscattered on high energy electron or proton beams can provide high energy, high luminosity photon-electron, photon-photon or photon-proton collisions. This allows the study of short-distance QCD processes such as high transverse momentum photon-photon and photo-production reactions, deep inelastic Compton scattering, the photon structure function, direct photon reactions, or searches for pseudo-Goldstone bosons and supersymmetry particles like the photino or goldstino. The relative reaction rates should be quite high since (1) photo-production cross sections are significantly larger than the corresponding electroproduction cross sections and (2) absence of the conventional beam-beam interaction allows significantly higher currents and smaller interaction areas. It thus seems possible to have photon luminosities much larger than for electrons. Examples are given using the PEP storage ring with the SLAC linac beam

[en] A key step in understanding the high energy particle populations and their emissions in active galactic nuclei and their plasma jets is a thorough consideration of photomeson production. Utilizing elementary particle physics phenomenology we calculate here the energy distribution of secondary pions arising from photon-proton collisions. The highly relativistic protons necessary for pion production in a radiation field are expected to be generated in shockwaves by the first-order Fermi process up to ∼10¹² GeV in the hot spots of radio galaxies and up to ∼10⁹ GeV in the compact cores. Due to the pion decay the resulting primary spectrum for the decay products high energy photons, neutrinos, electrons and positrons is basically the same. An electromagnetic cascade reprocessing the injected power of the pion decay products will feed back with the photon field and hence with the proton energy distribution. The photons emanating from this process can supply the majority of an AGN's hard X-ray and γ-ray luminosity which indeed has been shown to be linked to the nonthermal radio and infrared luminosity. This contrasts with models supporting the idea that either thermal comptonization or unresolved line emission is responsible for the high X-ray and γ-ray luminosity of AGN. We show that a rising p-γ interaction cross section expected from the hadronic properties of the photon could be detectable directly through the neutrino spectra of sources where relativistic protons cool in a nonthermal radiation field. The jet events could generate a hard component showing up above 10⁵ GeV pion energy in the particle injection distribution possibly leading to spectral signatures in the γ-ray emission of active galaxies

[en] The new code CCC-0514-ANISN/PC is described, as well as a ''GENERAL DESCRIPTION OF ANISN/PC code''. In addition to the ANISN/PC code, the transmittal package includes an interactive input generation programme called APE (ANISN Processor and Evaluator), which facilitates the work of the user in giving input. Also, a 21 group photon cross section master library FLUNGP.LIB in ISOTX format, which can be edited by an executable file LMOD.EXE, is included in the package. The input and output subroutines are reviewed. 6 refs, 1 fig., 1 tab

[en] The Gamma Physics (GaP) program of physical phenomena investigation is proposed on γp, γe and γγ colliders at TeV energies. The program contains specialized software (CompHEP system) created for automation of particle interaction processes calculations in the framework of various gauge models. Preliminary physical results are presented (heavy quark production, W, Z production, supersymmetry etc.), and further software development is suggested. (R.P.) 22 refs., 8 figs., 4 tabs

[en] We discuss a simple time of flight technique for measurement of temperature of a cold cloud in a magneto-optical trap (MOT). The technique is based on spatiotemporal fluorescence imaging of the cloud that is allowed to undergo one-dimensional expansion in the presence of the orthogonal two-dimensional configuration of laser beams by temporal modulation of a pair of counterpropagating trapping beams in the MOT. We show that, in the time scale 0≤t<5 ms, the expansion of the cloud is ballistic and the temperature can be extracted from the time variation of the rms size of the cloud in the expansion direction. The reliability of the technique has been established by comparing the results with release and recapture method, and also by fitting them to the known temperature scaling law

[en] Short communication

No abstract available

[en] The definition of the virtual photon impact factor involves the integration of the s-channel discontinuity of the photon-Reggeon scattering amplitude over the right cut. It permits to formulate a new approach for the calculation of the impact factor based on analytical properties of the amplitude in question. In the next-to-leading order it may give a possibility for considerable simplification of the calculation. We have shown that a part of the diagrams contributing to the impact factor can be treated without their real calculation

[en] In the case of excitation of luminescence of free molecules by a beam of fast electrons a connection is found in the Born approximation between its anisotropy and that induced as the result of excitation by linearly polarized light. This connection is confirmed experimentally. We note that such a connection is also possible in the process of rotational relaxation of induced anisotropy, including collisional