The double-charm tetraquark (T+cc, ccud) is a type of long-lived tetraquark that was discovered in 2021 in the LHCb experiment conducted at the Large Hadron Collider.

[1] The discovery showed an exceptionally strong peak, with 20-sigma significance.

[6] It is hypothesized that studying the behavior of the double-charm tetraquark may play a part in explaining the behavior of the strong force.

[7] Following the discovery of the T+cc, researchers now plan experiments to find its double-beauty counterpart Tbb.

[8] This tetraquark has been found to have a longer lifespan than most known exotic-matter particles.