🔬 The LHC detects a new particle, awaited for over 20 years

A subatomic particle long predicted by theorists has finally been observed, ending a decades-long wait in physics.

Named Ξcc+ (Xi-cc plus), this entity resembles the proton but has a greater mass, as it is formed from two charm quarks and one down quark. Its detection was made possible thanks to the upgraded LHCb detector at the CERN Large Hadron Collider (LHC). An international collaboration involving over a thousand scientists made this discovery possible.


To identify the Ξcc+, physicists analyzed its decay into lighter particles during proton-proton collisions. A clear signal, corresponding to a mass of 3619.97 MeV/c², was recorded. This measurement agrees with theoretical predictions established from an already known related particle, thereby confirming the model's validity.

This observation resolves a scientific debate that has lasted for over twenty years, where previous claims about the existence of this particle had never been verified. The measured mass of the detected particle perfectly aligns with the expectations of the latest theories, providing the long-awaited confirmation.

Quarks and Particle Formation

Quarks are fundamental constituents of matter, which combine to form hadrons like protons and neutrons. There are six types of quarks, including up, down, and charm, each with distinct properties such as mass and electric charge. These particles interact via the strong force, one of the fundamental forces of nature, which holds them together in stable or semi-stable configurations.

When three quarks assemble, they form baryons, a category that includes the proton, composed of two up and one down, and the Ξcc+, with two charm and one down. The mass of a baryon depends largely on the types of quarks involved; charm quarks being heavier, the Ξcc+ has a mass greater than that of the proton. This diversity of combinations allows physicists to test the predictions of the Standard Model of particle physics.

The discovery of the Ξcc+ teaches us about how heavy quarks can organize themselves. It validates theories developed over many years and paves the way for the study of other exotic particles. By exploring these assemblies, researchers hope to decipher the mechanisms that govern matter.

This advance encourages future research aimed at mapping all possible particles, thus contributing to a more complete picture of the Universe at its smallest scale.