Dijet imbalance in hadronic collisions

TL;DR

This paper explores how polarization effects of initial state partons, such as transversely polarized quarks and linearly polarized gluons, influence dijet imbalance measurements in hadronic collisions, complicating the extraction of parton transverse momentum.

Contribution

It introduces the impact of initial state parton polarization on dijet imbalance and proposes weighted cross sections to isolate these effects, advancing understanding of jet broadening.

Findings

Polarization effects induce azimuthal dependences in dijet production.

These effects influence jet broadening observables used to measure parton transverse momentum.

Weighted cross sections can help isolate polarization contributions.

Abstract

The imbalance of dijets produced in hadronic collisions has been used to extract the average transverse momentum of partons inside the hadrons. In this paper we discuss new contributions to the dijet imbalance that could complicate or even hamper this extraction. They are due to polarization of initial state partons inside unpolarized hadrons that can arise in the presence of nonzero parton transverse momentum. Transversely polarized quarks and linearly polarized gluons produce specific azimuthal dependences of the two jets that in principle are not suppressed. Their effects cannot be isolated just by looking at the angular deviation from the back-to-back situation, rather they enter jet broadening observables. In this way they directly affect the extraction of the average transverse momentum of unpolarized partons that is thought to be extracted. We discuss appropriately weighted cross sections to isolate the additional contributions.