Jet Angularities in Z+jet production at the LHC

TL;DR

This paper provides a comprehensive theoretical and phenomenological analysis of jet angularities in Z+jet events at the LHC, combining Monte Carlo simulations, NLO calculations, and resummation techniques to predict distributions for upcoming experimental measurements.

Contribution

It introduces a combined approach of Monte Carlo, NLO, and NLL resummation for jet angularities, including soft emissions and non-global logarithms, with realistic experimental considerations.

Findings

Resummed predictions at NLL' accuracy for jet angularities.

Assessment of NLO matching and merging effects on distributions.

Predictions compatible with upcoming LHC measurements.

Abstract

We present a phenomenological study of angularities measured on the highest transverse-momentum jet in LHC events that feature the associate production of a $Z$ boson and one or more jets. In particular, we study angularity distributions that are measured on jets with and without the SoftDrop grooming procedure. We begin our analysis exploiting state-of-the-art Monte Carlo parton shower simulations and we quantitatively assess the impact of next-to-leading order (NLO) matching and merging procedures. We then move to analytic resummation and arrive at an all-order expression that features the resummation of large logarithms at next-to-leading logarithmic accuracy (NLL) and is matched to the exact NLO result. Our predictions include the effect of soft emissions at large angles, treated as a power expansion in the jet radius, and non-global logarithms. Furthermore, matching to fixed-order is performed in such a way to ensure what is usually referred to as NLL$'$ accuracy. Our results account for realistic experimental cuts and can be easily compared to upcoming measurements of jet angularities from the LHC collaborations.