LHCb reports the observation of a new particle with two charm and one up quark. The mass is about 3621 MeV, which is almost four times heavier than the proton. It is the first time that such a particle has been unambiguously detected.
At the EPS Conference on High Energy Physics, EPS-HEP 2017, in Venice, Italy, the LHCb collaboration presented the first observation of a doubly charmed particle. This particle, called the Ξcc++, is a baryon (particle composed of three quarks) containing two charm quarks and one up quark, resulting in an overall doubly positive charge. It is a doubly charm counterpart of the well-known lower mass Ξ0 baryon, which is composed of two strange quarks and an up quark (LHCb publication).
The following plot shows the invariant mass distribution of the candidates.