  A scaling law analysis of the world data on inclusive large-pT hadron
production in hadronic collisions is carried out. A significant deviation from
leading-twist perturbative QCD predictions at next-to-leading order is
reported. The observed discrepancy is largest at high values of xT=2pT/sqrt(s).
In contrast, the production of prompt photons and jets exhibits the scaling
behavior which is close to the conformal limit, in agreement with the
leading-twist expectation. These results bring evidence for a non-negligible
contribution of higher-twist processes in large-pT hadron production in
hadronic collisions, where the hadron is produced directly in the hard
subprocess rather than by gluon or quark jet fragmentation. Predictions for
scaling exponents at RHIC and LHC are given, and it is suggested to trigger the
isolated large-pT hadron production to enhance higher-twist processes.
