Experimental Search For Interference Effects In qq At LHC

TL;DR

This study investigates interference effects between electroweak and QCD processes in hadronic Z decays at the LHC, comparing simulations with experimental data, especially at low transverse momenta, to validate current modeling approaches.

Contribution

It provides the first experimental assessment of interference effects in low transverse momentum regions at the LHC, testing the validity of existing simulation strategies.

Findings

Three sigma evidence for ZZ to bb mu mu at low pT

No conclusive evidence of interference effects due to large mass peak errors

Current simulation strategies remain adequate for LHC analyses

Abstract

At present, the simulations for hadronic Z decay used at the Large Hadron Collider (LHC) neglect the effects of interference between the electroweak production of the hadronic Z boson and the Quantum Chromodynamics (QCD) production of $q\bar{q}$. Indeed, the diboson Monte Carlo samples are generated independently from QCD processes. The purpose of this project is to assess the validity of this simulation approach by studying these interference effects, comparing Monte Carlo samples to experimental data. In particular, regions of low transverse momenta are explored for the first time, revealing new challenges unique to these regions. Three sigma evidence for ZZ $\rightarrow$ $b\bar{b}\mu\bar{\mu}$ is found at low transverse momenta for the very first time. However, the error on the mass peak is too large to provide any sufficient evidence for interference. As such, there is no evidence to suggest that the simulation strategies adopted at the LHC are inadequate.