Higher-Twist Dynamics in Large Transverse Momentum Hadron Production

TL;DR

This paper analyzes large transverse momentum hadron production data, revealing significant deviations from perturbative QCD predictions and providing evidence for higher-twist contributions, especially at high xT, with implications for RHIC and LHC experiments.

Contribution

It presents the first comprehensive scaling law analysis showing the importance of higher-twist processes in large-pT hadron production, contrasting with prompt photon and jet production.

Findings

Deviations from leading-twist QCD predictions at high xT.

Prompt photon and jet production follow expected scaling behavior.

Higher-twist processes contribute significantly to hadron production.

Abstract

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.