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The production of φ mesons in proton collisions with C, Cu, Ag, and Au targets has been studied via the φ → K + K − decay at an incident beam energy of 2.83 GeV using the ANKE detector system at COSY. For the first time, the momentum dependence of the nuclear transparency ratio, the in-medium φ width, and the differential cross section for φ-meson production at forward angles have been determined for these targets over the momentum range of 0.6-1.6 GeV/c. There are indications of a significant momentum dependence in the value of the extracted φ width, which corresponds to an effective φN absorption cross section in the range of 14-21 mb.

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The new distant metagalactic γ-sources 1739+522 ( z = 1.375) and 3c454.3 ( z = 0.857) are detected at energies E > 0.8 TeV with the fluxes (0.53 ± 0.10) × 10-12 cm -2 s -1 and (0.43 ± 0.13) × 10-12 cm -2 s -1, respectively. The γ-ray spectra and fluxes of known blazars Mkn 421, Mkn 501 and distant flat-spectrum radio quasars 1739+522 and 3c454.3 are presented.