# New physics searches with heavy-ion collisions at the LHC

## TL;DR

This paper explores the potential for discovering new physics phenomena in heavy-ion collisions at the LHC, highlighting unique opportunities beyond standard proton-proton studies, including searches for exotic particles and interactions.

## Contribution

It proposes specific new physics searches in heavy-ion mode at the LHC, emphasizing their unique discovery potential and scientific motivation beyond traditional quark-gluon plasma research.

## Key findings

- Heavy-ion collisions can probe new particles like axion-like pseudoscalars and dark photons.
- Ultraperipheral interactions offer access to non-linear QED effects.
- Potential for high-luminosity data collection beyond 2030 enhances discovery prospects.

## Abstract

This document summarises proposed searches for new physics accessible in the heavy-ion mode at the CERN Large Hadron Collider (LHC), both through hadronic and ultraperipheral $\gamma\gamma$ interactions, and that have a competitive or, even, unique discovery potential compared to standard proton-proton collision studies. Illustrative examples include searches for new particles -- such as axion-like pseudoscalars, radions, magnetic monopoles, new long-lived particles, dark photons, and sexaquarks as dark matter candidates -- as well as new interactions, such as non-linear or non-commutative QED extensions. We argue that such interesting possibilities constitute a well-justified scientific motivation, complementing standard quark-gluon-plasma physics studies, to continue running with ions at the LHC after the Run-4, i.e. beyond 2030, including light and intermediate-mass ion species, accumulating nucleon-nucleon integrated luminosities in the accessible fb$^{-1}$ range per month.