[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

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[en] Short communication

[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] The study of nuclear matter under extreme conditions is a very active area in nuclear physics. This study may improve our understanding of the equation of states and liquid-gas phase transitions in nuclear matter as well as the spectroscopic and dynamic characterization of exotic nuclear systems and reactions. A clear characterization of nuclear interacting systems requires probing the spacetime properties of various particle-emitting sources and the knowledge of the reaction mechanism. Particle-particle correlations represent a very powerful technique to study emitting sources produced during a reaction. In this work two-proton correlation functions measured in Xe+Au at E = 50MeV/nucleon have been studied. By using angle-averaged two-proton correlation functions and imaging techniques we have estimated some of the basic proprieties, such as the size and the relative contributions provided by two-particle–emitting sources produced in semi-central collisions and characterized by different emission time-scales.

[en] Recent proton Compton scattering data from Saskatoon spanning the pion threshold region are shown to reflect the presence of a unitarity cusp (Wigner cusp), long predicted but never before observed. The analysis is based on a formulation of the Compton cross section employing convenient semiphenomenological expressions for the four dominant multipole amplitudes, designed to respect the low energy theorem and other constraints. Unitarity anomalies have now been detected in both the elastic (Compton) and inelastic (π⁰p) channels of the γ+p reaction

[en] We show that the geometric scaling of the total virtual photon-proton cross section data can be explained using standard linear Dokshitzer-Gribov-Altarelli-Parisi perturbative evolution with generic boundary conditions in a wide kinematic region. This allows us to single out the region where geometric scaling may provide evidence for parton saturation

No abstract available

No abstract available