Search for heavy long-lived multi-charged particles in the full LHC Run 2 pp collision data at √s = 13 TeV using the ATLAS detector

A search for heavy long-lived multi-charged particles is performed using the ATLAS detector at the LHC. Data collected in 2015–2018 at √s = 13 TeV from pp collisions corresponding to an integrated luminosity of 139 fb⁻¹ are examined. Particles producing anomalously high ionization, consistent with long-lived spin-½ massive particles with electric charges from |q| = 2e to |q| 7e are searched for. No statistically significant evidence of such particles is observed, and 95% confidence level cross-section upper limits are calculated and interpreted as the lower mass limits for a Drell–Yan plus photon-fusion production mode. The least stringent limit, 1060 GeV, is obtained for |q| = 2eparticles, and the most stringent one, 1600 GeV, is for |q| particles.