Minijets and transverse energy flow in high energy collisions

When studying the production of minijets and transverse energy flow in high energy hadron-hadron or nucleus-nucleus collisions, two essential points have to be taken into account. First, one has to account for the virtuality of the colliding partons and, second, it is important to avoid double counting, when many links in a parton chain can be interpreted as the momentum transfer in a hard subcollision. The linked dipole chain model, introduced for low-x DIS, is particularly suitable for a study of these problems. It describes (mini)jet production in a k(perpendicular to)-factorizing formalism, which includes all links in a parton chain on an equal footing, avoiding double counting. In a "naive" calculation based on integrated structure functions, the cross section blows up for small p(perpendicular to), which makes it necessary to introduce a soft cutoff. In our approach we find a dynamical suppression at low p(perpendicular to), which makes it possible to extrapolate to higher energies and make more reliable predictions for BNL RHIC and CERN LHC.