Ξcc++

The Xi double-charm baryon, denoted as ${\displaystyle \Xi _{\rm {cc}}^{++}}$, is a Xi baryon composed of two charm quarks and one up quark.^[1]

Its discovery by the LHCb Collaboration was announced on 6 July 2017 in Venice, Italy, at the European Physical Society Conference on High Energy Physics. ${\displaystyle \Xi _{\rm {cc}}^{++}}$ is the first baryon discovered with two heavy quarks (charm and/or bottom) and a light quark. Its mass is 3621 MeV, nearly four times that of the proton.^[2]

It was identified when it disintegrated into a ${\displaystyle \Lambda _{\rm {c}}^{+}}$ baryon and three lighter mesons, K^–, π⁺ and π⁺.