Physicists at the Large Hadron Collider have discovered a rare new particle that contains two "charm" quarks.
March 31, 2026
Original Paper
Observation of the doubly charmed baryon $\itΞ_{cc}^+$ with the LHCb Run 3 detector
arXiv · 2603.28456
The Takeaway
While common matter is made of light quarks, this new particle—the Xi_cc+—is a heavy, exotic relative of the proton. It is the first new particle discovered during the LHC’s latest high-energy mission, proving that our fundamental theories about how the strongest forces in nature glue matter together are correct even for the heaviest particles.
From the abstract
The first observation of the doubly charmed baryon $\it{\Xi}_{cc}^+$ is reported through its decay to the $\it{\Lambda}_c^+ K^-\pi^+$ final state, with a statistical significance exceeding seven standard deviations. The observation is made using proton-proton collision data collected in 2024 with the LHCb Run 3 detector at a center-of-mass energy of 13.6 TeV, corresponding to a total integrated luminosity of $6.9\,\mathrm{fb}^{-1}$. The $\it{\Xi}_{cc}^+$ mass is measured to be $3619.97 \pm 0.83