Strong field QED in lepton colliders and electron/laser interactions

Abstract

Studies of strong field particle physics processes in electron/laser interactions and lepton collider interaction points are reviewed. These processes are defined by the high intensity of the electromagnetic fields involved and the need to take them into account as fully as possible. Thus, the main theoretical framework considered is the Furry interaction picture within intense field quantum field theory. In this framework, the influence of a background electromagnetic field in the Lagrangian is calculated non perturbatively, involving exact solutions for quantised charged particles in the background field. These "dressed" particles go on to interact perturbatively with other particles, enabling the background field to play both a macroscopic and microscopic role. Macroscopically, the background field starts to polarise the vacuum, in effect rendering it a dispersive medium. Particles encountering this dispersive vacuum obtain a lifetime, either radiating or decaying into pair particles at a rate dependent on the intensity of the background field. In fact, the intensity of the background field enters into the coupling constant of the strong field quantum electrodynamic Lagrangian, influencing all particle processes. A number of new phenomena occur. Particles gain an intensity dependent rest mass shift that accounts for their presence in the dispersive vacuum. Multi photon events involving more than one external field photon occur at each vertex. Higher order processes which exchange a virtual strong field particle, resonate via the lifetimes of the unstable strong field states. Two main arenas of strong field physics are reviewed; those occurring in relativistic electron interactions with intense laser beams, and those occurring in the beam beam physics at the interaction point of colliders. This review outlines the theory, describes its significant novel phenomenology and details the experimental schema required to detect strong field effects and the simulation programs required to model them.

Letter of Intent for the LUXE Experiment

“…The MC simulation relies on a calculation similar to those described in Refs. [27,48]. Both the e + nγ L and the γ B + nγ L process are generated.…”

Measuring the boiling point of the vacuum of quantum electrodynamics

“…The solutions which allow for the transverse focussing lead to the conclusion that the Volkov solution with IPW assumption can be used as long as the local value of the strong laser intensity, at the point of pair production, is taken into account. This is necessarily the case for any strong field PIC code that simulates the pair production in a real bunch/pulse interaction [32].…”

“…To leading order in Furry picture [23] perturbation theory (for a recent review, see Ref. [32]), the rate of laserassisted OPPP can be written in the form…”