A particle composed of 2 quarks is called a?

A particle composed of two quarks is called a meson. Mesons are a type of hadron, which are particles that experience the strong nuclear force. They are specifically formed from one quark and one antiquark. The quark-antiquark pair allows for a variety of meson particles, each with different properties.

In contrast, baryons are another type of hadron but are made up of three quarks. This distinction is important because it directly relates to the particle's structure and the interactions it undergoes. Fermions refer to a broader category of particles that obey the Pauli exclusion principle, which includes baryons and mesons, but it is not specific enough to identify a two-quark composition. Photons are fundamental particles of light and do not contain quarks, further separating them from the category of mesons.