Angular distribution for the electron recoil in pair production by linearly polarized γ- rays on electrons

摘要

In this work we study the angular distribution of electron recoil in pair production by linearly polarized gamma rays in the electron electric field. We also present a new algorithm for the simulation of this cross-section for the polar and azimuthal angle distributions for the recoil electron obtained from the cross section calculated using the Borsellino diagrams in the high energy limit ([1] E.A. Vinokurov, E.A. Kurae, Sov. Phys. JETP 36 (1973) 602). Although this process has a lower probability than the pair production in the nucleus field (～ 1/Z), it is nevertheless interesting since the azimuthal distribution of the recoil electron is highly sensitive to the polarization of the incoming gamma radiation. This process is also interesting for the fact that in the range of Born approximation, the distribution of the polar and azimuthal angles of the electron recoil momentum does not depend explicitly on photon energy. This is important in astrophysics since the astrophysical sources are in general non-monochromatic. We insert the algorithm into the Geant4 toolkit and made simple simulation to test the method.