Transverse momentum distributions for heavy quark pairs.

We study the transverse momentum distribution for a pair of heavy quarks produced in hadron-hadron interactions. Predictions for the large transverse momentum region are based on exact order αs QCD perturbation theory. For the small transverse momentum region, we use techniques for all orders resummation of leading logarithmic contributions associated with initial state soft gluon radiation. The combination provides the transverse momentum distribution of heavy quark pairs for all transverse momenta. Explicit results are presented for bb̄ pair production at the Fermilab Tevatron collider and for cc̄ pair production at fixed target energies.