The new particles have been discovered using the Large Hadron Collider as part of the third round of collisions. After 3 years of inactivity, LHC is back in action.
About the new particles
The latest discoveries include the pentaquark, the doubly-charged tetraquark, and its neutral partner. They were found in the analysis of decays of B-mesons.
What are quarks?
Quarks are elementary particles that usually combine in groups of two or three to form hadrons like protons and neutrons. Rarely they combine to form tetraquarks and pentaquarks.
Significance of new particles
The new kind of pentaquark and the first duo of tetraquarks will provide a better understanding of the strong force that holds the nuclei of atoms together.