Synchrotron radiation and pair creation of massless charges in magnetic field

Abstract

We study the massless limit in synchrotron radiation and one-photon pair creation in magnetic field. In this limit Schwinger critical field $H_0=m^2{c}^3/(e\hslash )$ tends to zero, so two characteristic quantum parameters $\eta =H/H_0,\chi =\eta E/m{c}^2$ are infinite, and the standard approximations used in analytical calculations fail. Applying Schwinger's proper time methods we derive simple expressions for synchrotron radiation spectra emitted by massless charges of spins $s=0,1/2$ and the pair creation probability distribution in the quasiclassical (high Landau levels) regime exhibiting simple scaling properties and possessing universal spectral shapes.

Comments: 6 pages, 2 figures, Proc. of 14th Marcel Grossmann Meeting on Recent Developments in Theoretical and Experimental General Relativity, Astrophysics, and Relativistic Field Theories (MG14), 12-18 Jul 2015, Rome, Italy, 2016 Conference: C15-07-12