Assisted neutrino pair production in combined external fields

Neutrino--antineutrino ($\nu\bar\nu$) pair production is one of the main processes responsible for the energy loss of stars. Apart from the collision of two ($\gamma\gamma\to\nu\bar\nu$) or three ($\gamma\gamma\gamma\to\nu\bar\nu$) real photons, pair creation from a photon and photon collisions in the presence of nuclear Coulomb fields or external magnetic fields have been considered previously. Here, we study a pair production of neutrino and antineutrino from a low-energy photon in the presence of a combined homogeneous magnetic field and the Coulomb field of a nucleus with charge number $Z$.