Single-Inclusive Production of Hadrons and Jets in Lepton-Nucleon Scattering at NLO

TL;DR

This paper provides NLO perturbative-QCD calculations for lepton-nucleon scattering producing hadrons and jets, highlighting their potential for studying transverse spin effects and analyzing the significance of photon exchange contributions.

Contribution

It offers the first NLO calculations for these processes and explores their use in probing transverse spin phenomena in QCD.

Findings

NLO corrections are significant for the spin-averaged cross section.

Photon exchange (Weizs"{a}cker-Williams) contributions are analyzed.

Numerical estimates are provided for fixed target and future collider experiments.

Abstract

We present next-to-leading order (NLO) perturbative-QCD calculations of the cross sections for $\ell N\to h X$ and $\ell N\to \mathrm{jet}\, X$. The main feature of these processes is that the scattered lepton is not observed, so that the hard scale that makes them perturbative is set by the transverse momentum of the hadron or jet. Kinematically, the two processes thus become direct analogs of single-inclusive production in hadronic collisions which, as has been pointed out in the literature, makes them promising tools for exploring transverse spin phenomena in QCD when the incident nucleon is transversely polarized. We find that the NLO corrections are sizable for the spin-averaged cross section. We also investigate in how far the scattering is dominated by the exchange of almost real (Weizs\"{a}cker-Williams) photons. We present numerical estimates of the cross sections for present-day fixed target experiments and for a possible future electron ion collider.