Quark

Quarks are elementary particles that form the building blocks of matter. They join together to create composite particles known as hadrons, including protons and neutrons found in atomic nuclei. The most common types of observable matter consist of up quarks, down quarks, and electrons. Due to the principle of color confinement, quarks are always bound within hadrons like baryons and mesons, or in quark–gluon plasmas. Consequently, much of our understanding of quarks stems from studying hadrons.