Performance of pile-up mitigation techniques for jets in $pp$ collisions at $\sqrt{s} = 8$ TeV using the ATLAS detector

TL;DR

This paper evaluates and compares various pile-up mitigation techniques for jets in proton-proton collisions at 8 TeV using ATLAS data, focusing on energy correction, jet association, and shape mitigation methods.

Contribution

It introduces and assesses advanced pile-up correction and mitigation methods for jets, including energy density estimates, tracking-based association, and shape grooming techniques.

Findings

Effective pile-up correction methods improve jet energy resolution.

Jet shape mitigation techniques reduce pile-up contamination.

Performance projections for future collider conditions are discussed.

Abstract

The large rate of multiple simultaneous proton--proton interactions, or pile-up, generated by the Large Hadron Collider in Run 1 required the development of many new techniques to mitigate the adverse effects of these conditions. This paper describes the methods employed in the ATLAS experiment to correct for the impact of pile-up on jet energy and jet shapes, and for the presence of spurious additional jets, with a primary focus on the large 20.3 fb$^{-1}$ data sample collected at a centre-of-mass energy of $\sqrt{s} = 8$ TeV. The energy correction techniques that incorporate sophisticated estimates of the average pile-up energy density and tracking information are presented. Jet-to-vertex association techniques are discussed and projections of performance for the future are considered. Lastly, the extension of these techniques to mitigate the effect of pile-up on jet shapes using subtraction and grooming procedures is presented.