  We propose a new method to determine at what transverse momenta particle
production in high-energy pp collisions is governed by hard parton-parton
processes. Using information on the transverse spatial distribution of partons
obtained from hard exclusive processes in ep/gamma p scattering, we evaluate
the impact parameter distribution of pp collisions with a hard parton-parton
process as a function of p_T of the produced parton (jet). We find that the
average pp impact parameters in such events depend very weakly on p_T in the
range 2 < p_T < few 100 GeV, while they are much smaller than those in
minimum-bias inelastic collisions. The impact parameters in turn govern the
observable transverse multiplicity in such events (in the direction
perpendicular to the trigger particle or jet). Measuring the transverse
multiplicity as a function of p_T thus provides an effective tool for
determining the minimum p_T for which a given trigger particle originates from
a hard parton-parton process. Additional tests of the proposed geometric
correlations are possible by measuring the dependence on the trigger rapidity.
Various strategies for implementing this method are outlined.
