# Search for high-mass dilepton resonances using 139 fb$^{-1}$ of $pp$ collision data collected at $\sqrt{s}=$13 TeV with the ATLAS detector

## TL;DR

This paper reports a comprehensive search for high-mass dilepton resonances at the LHC using ATLAS data, finding no evidence of new particles and setting limits on various theoretical models up to 4.5 TeV.

## Contribution

It provides the most extensive limits to date on high-mass dilepton resonances using 139 fb$^{-1}$ of data at 13 TeV, covering multiple spin hypotheses and models.

## Key findings

- No significant excess observed in dilepton mass spectrum.
- Limits set on resonance cross-section and mass for various models.
- Excludes Z' bosons below 4.5 TeV in certain models.

## Abstract

A search for high-mass dielectron and dimuon resonances in the mass range of 250 GeV to 6 TeV is presented. The data were recorded by the ATLAS experiment in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=$13 TeV during Run 2 of the Large Hadron Collider and correspond to an integrated luminosity of 139 fb$^{-1}$. A functional form is fitted to the dilepton invariant-mass distribution to model the contribution from background processes, and a generic signal shape is used to determine the significance of observed deviations from this background estimate. No significant deviation is observed and upper limits are placed at the 95% confidence level on the fiducial cross-section times branching ratio for various resonance width hypotheses. The derived limits are shown to be applicable to spin-0, spin-1 and spin-2 signal hypotheses. For a set of benchmark models, the limits are converted into lower limits on the resonance mass and reach 4.5 TeV for the E6-motivated $Z^\prime_\psi$ boson. Also presented are limits on Heavy Vector Triplet model couplings.