Hadronic Final States

TL;DR

This article surveys hadronic final states in deep inelastic scattering as a stringent test of QCD beyond inclusive structure functions. It covers jet physics, including NLO predictions for 2+1 jets, multiple jet definitions, $α_s$ extraction, event shapes, and power corrections, along with fragmentation studies in the current jet. It then analyzes small-$x$ final states under BFKL/CCFM and DGLAP frameworks, highlighting transverse energy flow and forward jet signatures as discriminants, with HERA data hinting at non-DGLAP dynamics. The discussion on exotic QCD explores instanton-induced processes, their distinctive high-multiplicity, isotropic signatures, and current theoretical/experimental prospects. Together, the sections argue that DIS final states illuminate perturbative/non-perturbative interface and offer avenues to test universality of power corrections and small-$x$ dynamics.

Abstract

The following aspects of hadronic final states in deep inelastic lepton scattering are reviewed: measuring $alpha_s$ from multi-jet production rates and event shapes; alternative jet algorithms for DIS; power-suppressed corrections to event shapes; comparing jet fragmentation in $e^+e^-$ annihilation and DIS; final states in the BFKL and CCFM formulations of small-$x$ dynamics; exotic (instanton-induced) final states.