The ATLAS Collaboration used the full LHC Run-2 dataset (collected 2015–2018) to analyse all-charm tetraquark decays into two channels.

In a new analysis presented at the ICHEP 2022 conference, ATLAS physicists found evidence of a four-charm-quark excess. Like the LHCb Collaboration, ATLAS sees both the X(6900) particle and a broad structure at threshold.