Power corrections to the production of a color-singlet final state in hadron collisions in the N-jettiness slicing scheme at NLO QCD

TL;DR

This paper calculates next-to-leading power corrections for colorless final state production in hadron collisions using the N-jettiness slicing scheme at NLO QCD, highlighting process dependence at subleading power.

Contribution

It develops a method to compute power corrections at NLO QCD for zero-jettiness, addressing process dependence and utilizing Berends-Giele currents for high-multiplicity states.

Findings

Power corrections can be computed using Berends-Giele currents.

Universality of leading power does not extend to subleading power in collinear limits.

Method applied to lepton pair and multi-photon production in q q̄ collisions.

Abstract

We compute next-to-leading power corrections in the zero-jettiness variable for the production of colorless final states at hadron colliders at next-to-leading order in QCD. To assess if the process-independence of leading power contributions can be extended, we attempt to construct generic expansions of phase spaces and matrix elements squared through next-to-leading power in the zero-jettiness. We highlight challenges associated with the collinear limit, where universality no longer holds at the subleading power, making the result process-dependent. We show that quantities that need to be calculated in the collinear limit can be obtained using Berends-Giele currents, enabling computation of power corrections to high-multiplicity final states. As a concrete example, we apply our method to compute power corrections in the zero-jettiness for lepton pair as well as multi-photon production in $q \bar q$ collisions.