ATLAS observes new Bc meson excited state

Protons and neutrons—the building blocks of matter—belong to a huge class of particles called hadrons. Hadrons are composite particles made of quarks that are bound together by the strong force. They are classified into two groups: baryons, which consist of three quarks (like protons and neutrons), and mesons, which are formed by a quark–antiquark pair.

المصدر: Phys.org