Excess of soft dielectrons and photons

Abstract

Spectra of unbound electron-positron pairs (dielectrons, in brief) and photons from decays of parapositronia produced in ultraperipheral collisions of electrically charged objects are calculated. Their shapes at energies of the NICA collider are demonstrated. Soft dielectrons and photons are abundantly produced. The relevance of these processes to the astrophysical problem of cooling electron-positron pairs and the intense emission of 511 keV photons from the Galactic center is discussed.

Comments: 10 pages, 2 Figures