New effects in the ISR region

We suggest that the increase of total cross sections and large P_T effects observed over the ISR range have a common origin in the hard collision of parton pairs. The observed magnitude of these effects suggest a parton-parton cross section ～ 0.2 mb. The data is consistent with vector gluon exchange mechanisms. These mechanisms can also cause inhibited shrinkage and energy dependent dips in differential cross sections.