Pair Production In Ultrarelativistic Collisions Research Articles

Finite-size and dynamical effects in pair production by an external field.

We evaluate the rate of pair production in a uniform electric field confined to a bounded region in space. Using the Balian-Bloch expansion of Green's functions we obtain explicit expressions for finite-size corrections to Schwinger's formula. The case of a time-dependent boundary, relevant to describe energy deposition by quark-antiquark pair production in ultrarelativistic collisions, is also investigated. We find that finite-size effects are important in nuclear collisions. They decrease when the strength of the chromoelectric field between the nuclei is large. As a result, the rate of energy deposition increases sharply with the mass number $A$ of the colliding nuclei.

Energy deposition by dynamical pair production in ultrarelativistic collisions

We investigate a mechanism of energy deposition through dynamical pair production in ultrarelativistic collisions. This mechanism arises because of the time dependence of the color charges created at the early stage of the reaction. We argue that such a mechanism may become comparable with that of Schwinger at high energies (about 1 TeV per nucleon CM). We discuss the production rates of heavy flavors and their energy dependence. We point out that this mechanism should be kept in mind when discussing signatures of a quark-gluon plasma formation.