Color fields on the light-shell

Abstract

We study the classical color radiation from very high energy collisions that produce colored particles. In the extreme high energy limit, the classical color fields are confined to a light-shell expanding at c and are associated with a non-linear σ-model on the 2D light-shell with specific symmetry breaking terms. We argue that the quantum version of this picture exhibits asymptotic freedom and may be a useful starting point for an effective light-shell theory of the structure between the jets at a very high energy collider.

Photon propagator in light-shell gauge

“…In the process of this derivation, we have presented a technique that may also be useful for calculations in other non-covariant gauges (and, we hope, other applications). LSG is a crucial part of the construction of the light-shell effective theory [1], which we hope may provide a new viewpoint for high-energy scattering in gauge theories. We also hope that further insight can be gained once this method is extended to non-abelian gauge theories.…”

“…In this paper we calculate the photon propagator in what we have called light-shell gauge (LSG). The motivation for working in LSG is described in depth in [1] (and [2]) where we discuss light-shell effective theory (LSET). We hope that LSET, for which LSG is an essential ingredient, may eventually provide another way of looking at high-energy scattering in gauge theories.…”

“…While perturbative computations in gauge theories are most commonly carried out in covariant gauges, where the procedure has been well established [3] there are venues in which non-covariant gauges may be preferable. In this paper we derive the photon propagator in light-shell gauge, which is defined by the condition v µ A µ = 0 (1) where…”

“…As a result, it is often convenient to use a position space formulation rather than momentum space formulation. While these gauges share some characteristics, only LSG guarantees zero field strength off of the light-shell [1] and allows for simplification of calculations in LSET [2]. Another important difference is that the radial gauge condition is invariant under homogeneous Lorentz transformations, while LSG is only invariant under rotations about the origin.…”

Towards an effective field theory on the light-shell

“…Previously, [1] we expressed the hope of constructing an effective field theory on the 2dimensional light-shell emerging from a high-energy collision. The idea was motivated by a classical picture of a very high energy hadronic collision in which colored particles are produced from an initially color-neutral state at t = r = 0 and instantaneously accelerate outward to the speed of light.…”