Constraints on parton-parton cross sections from large p(transverse) angular correlations

Recent data on rapidity distributions opposite a large p(transverse) trigger are analyzed. These data are found to constrain the angular dependence of the hard collision subprocess strongly. Estimates are given for quark-meson and quark-quark scattering. Using these results the behaviour of the position of the maximum of the opposite-side rapidity distribution is studied for larger values of the trigger x(transverse) and for different trigger and beam particles. (Auth.)