Probing underlying event in Z-boson events using event shape observables

TL;DR

This paper investigates whether combining event shape observables with underlying event measurements in Z-boson events can help distinguish the underlying event effects from initial state radiation jets at the LHC.

Contribution

It introduces a method to use event shape observables alongside traditional UE observables to better separate underlying event effects from ISR jets.

Findings

Event shape observables can enhance the discrimination of UE effects from ISR jets.

Combining observables improves understanding of the underlying event in Z-boson events.

The approach aids in more accurate modeling of the LHC environment.

Abstract

Experimental measurements of observables sensitive to the underlying event (UE) in $Z$-boson events have been performed by both ATLAS and CMS experiments at the LHC. However, in the busy LHC environment, these observables receive substantial contribution from jets originating from initial state radiation (ISR). We probe if using event shape observables in conjunction with the UE observables can help us to disentangle the effect of the UE from jets originating in ISR.