Higher-twist term in inclusive pion production at large transverse momentum

We calculate the absolute rate and kinematic dependence of the cross sections for the high-twist subprocesses $\mathrm{qG}\to \pi q$ and $q\overline{q}\to \pi G$ in perturbative quantum chromodynamics (QCD). These cross sections are used to estimate the high-twist contribution to large-transverse-momentum inclusive single-pion production in hadronic collisions. We compare the normalization of these terms with leading-order minimum-twist QCD processes such as $\mathrm{qG}\to \mathrm{qG}$. The high-twist contributions are shown to be quantitatively important for $p_T\widetilde{<}6$ ${\mathrm{GeV}}^2$ and $x_T\widetilde{>}0.5$, and they should be included in detailed analyses of data. We discuss cross sections and charge ratios, and we comment briefly about inclusive spin-correlation measurements at large $p_T$.