In this article, we investigate the contribution of the higher twist Feynman
diagrams to the large-pT inclusive pion production cross section in
proton-proton collisions and present the general formulae for the higher twist
differential cross sections in the case of the running coupling and frozen
coupling approaches. The structure of infrared renormalon singularities of the
higher twist subprocess cross section and the resummed expression (the Borel
sum) for it are found. We compared the resummed higher twist cross sections
with the ones obtained in the framework of the frozen coupling approximation
and leading twist cross section. We obtain, that ratio R for all values of
the transverse momentum pT of the pion identical equivalent to ratio r.
It is shown that the resummed result depends on the choice of the meson wave
functions used in calculation. Phenomenological effects of the obtained results
are discussed.Comment: 28 pages, 13 figure