Particle production in DIS off a shockwave in AdS

Abstract

Within the AdS/CFT correspondence, the shockwave metric has been widely used as a gravity dual for a fast moving nucleus. Here we propose a picture for particle production in deep inelastic scattering off a shockwave with the projectile represented by the $\mathcal{R}$-current. By using the method developed in \cite{Avsar:2009xf} to find an explicit expression for the scattered field, we are able to show that the scattered field can be written in terms of time-like and space-like vacuum states where the time-like states are identified with the outgoing particles. To support this picture, we calculate the contribution of the time-like modes to the energy-momentum tensor of the scattered field and show that the energy flow in the fifth dimension is directly related to the imaginary part of the action. The energy flow in the fifth dimension is also compared to the incoming energy flow to determine which fraction of the initial energy goes to the produced particles. The last two sections are devoted to localize the energy flow in momentum and coordinate space, first by finding the virtualities that contribute the most to the total flow, and second by finding an approximate trajectory in coordinate space.