Direct production of electron-positron pairs in photon collisions is one of the basic processes in the Universe. The linear Breit-Wheeler (BW) pair creation process (γ+γ to $e^+$+$e^-$), is the lowest threshold process in photon-photon interaction, controlling the energy release in Gamma Ray Bursts and Active Galactic Nuclei [1]. It is also responsible for the TeV cutoff in the photon energy...
Direct production of electron-position pairs in photon collisions is one of the basic processes in the Universe. The electron-positron production $\gamma+\gamma$ to $e^+$ +$ e^-$ (linear Breit-Wheeler process) is the lowest threshold process in photon-photon interaction, controlling the energy release in Gamma Ray Bursts, Active Galactic Nuclei, black holes and other explosive phenomena [1]....
Nambu and Goldstone have predicted emergence of massless boson (NGB) as a result of spontaneous symmetry breaking of a global symmetry. Originally the lightness of the pion mass was explained because pion is NGB as a result of chiral symmetry breaking. This guiding principle can be applied to any kinds of global symmetries. There are theoretically predicted NGBs which can be dark components in...
The energy of petawatt optical laser pulses of pico- and femto-second duration and relativistic intensities exceeding 1021 W/cm2 is efficiently converted to X-ray radiation, which is emitted by hot electron component in collision-less processes and heats the solid density plasma periphery. In turn, the intense X-ray radiation effectively ionizes the matter inside out, providing a large...
