Bright gamma-rays source and nonlinear Breit-Wheeler pairs in the collision of high density particle beams

Abstract

The collision of ultrashort high-density e^- or e^− and e^+ beams at 10s of GeV, to be available at the FACET II and in laser wakefield accelerator experiments, can produce highly collimated gamma rays (few GeVs) with peak brilliance of 10^27 ph/s mm^2 mrad^2 0.1% BW and up to 10^5 nonlinear Breit-Wheeler pairs. We provide analytical estimates of the photon source properties and of the yield of secondary pairs, finding excellent agreement with full-scale 3D self-consistent particle-in-cell simulations that include quantum electrodynamics effects. Our results show that beam-beam collisions can be exploited as secondary sources of gamma rays and provide an alternative to beam-laser setups to probe quantum electrodynamics effects at the Schwinger limit.