Antenna subtraction with hadronic initial states

TL;DR

This work extends the antenna subtraction formalism to include hadronic initial states, enabling IR-safe NLO (and outlining NNLO) calculations for collider observables with initial-state radiation. By crossing final-state antennae to initial-final and initial-initial configurations, the authors derive phase-space factorization, mappings, and integrated antenna functions needed for NLO, with explicit examples in DIS and hadron-hadron processes. The paper provides a comprehensive set of initial-state antennae (quark- and gluon-initiated) and phase-space mappings, demonstrating the method’s viability and outlining steps toward full NNLO implementations and potential coupling to parton showers. This advances precise QCD predictions for hadron collider phenomenology, including jet and vector-boson-plus-jet observables.

Abstract

The antenna subtraction method for the computation of higher order corrections to jet observables and exclusive cross sections at collider experiments is extended to include hadronic initial states. In addition to the already known antenna subtraction with both radiators in the final state (final-final antennae), we introduce antenna subtractions with one or two radiators in the initial state (initial-final or initial-initial antennae). For those, we derive the phase space factorization and discuss the allowed phase space mappings at NLO and NNLO. We present integrated forms for all antenna functions relevant to NLO calculations, and describe the construction of the full antenna subtraction terms at NLO on two examples. The extension of the formalism to NNLO is outlined.