Higher-twist contributions to large pT hadron production in hadronic collisions

TL;DR

This paper investigates deviations from QCD predictions in large-pT hadron production, attributing them to higher-twist processes where hadrons are produced directly, and discusses implications for collider physics.

Contribution

It provides evidence for significant higher-twist contributions in large-pT hadron production, contrasting with prompt photon and jet data, and offers predictions for RHIC.

Findings

Deviation from NLO QCD at high xT

Agreement of photon and jet data with leading-twist

Higher-twist processes impact collider signals

Abstract

The scaling behavior of large-pT hadron production in hadronic collisions is investigated. A significant deviation from the NLO QCD predictions is reported, especially at high values of xT=2pT/sqrt(s). In contrast, the prompt photon and jet production data prove in agreement with leading-twist expectations. These results are interpreted as coming from a non-negligible contribution of higher-twist processes, where the hadron is produced directly in the hard subprocess. Predictions for scaling exponents at RHIC are successfully compared to PHENIX preliminary measurements. We suggest to trigger on isolated large-pT hadron production to enhance higher-twist processes, and point that the use of isolated hadrons as a signal for new physics at colliders can be affected by the presence of direct hadron production processes.