title: Double-charm tetraquark
text: # Double-charm tetraquark
  
  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. It contains four quarks: two charm quarks, an anti-up and an anti-down quark.
  
  It has a theoretical computed mass of 3868±124 $MeV/c^2.$ The discovery showed an exceptionally strong peak, with 20-sigma significance.
  
  It is hypothesized that studying the behavior of the double-charm tetraquark may play a part in explaining the behavior of the strong force. Following the discovery of the $T^+$ $_{cc},$ researchers now plan experiments to find its double-beauty counterpart $T_{bb}.$ This tetraquark has been found to have a longer lifespan than most known exotic-matter particles.
  
  