Higher-twist effects in the direct photon production and the role of infrared renormalons

We calculate the contribution of the higher-twist effects to the large-p(T) inclusive single direct photon production cross section in pi p collisions in the running coupling and frozen coupling approaches within holographic QCD. We obtain the structure of infrared renormalon singularities of the higher-twist subprocess cross section. For a full analysis we compare the resummed higher-twist cross sections with the ones obtained in the framework of the frozen coupling approach and leading-twist cross section. DOI: 10.1103/PhysRevD.87.014006