What are quarks made of?

Quarks are already the smallest component. Quarks are the basic particles that participate in strong interactions and the basic units that make up matter.

Quarks combine with each other to form a composite particle called hadron. The most stable hadrons are protons and neutrons, which are the units that make up the nucleus.

Due to a phenomenon called quark confinement, quarks cannot be directly observed or separated, but can only be found in hadrons. For this reason, most of our knowledge about quarks comes indirectly from the observation of hadrons.

Extended data

Features:

Quarks have many different intrinsic properties, including charge, color charge, spin and mass. In the standard model of particle physics, quarks are the only elementary particles that can withstand all four basic interactions (electromagnetism, gravity, strong interaction and weak interaction). In addition, quarks are the only known particles whose elementary charge is non-integer.

Every flavor of quark has a corresponding antiparticle called antiquark. The only difference between antiquark and quark is that some of its characteristics are the same size as quark, but the sign is different.

Hadrons composed of quarks can be divided into baryons (with semi-odd spins) and mesons (with integer spins) according to their spins. All baryons, such as protons and neutrons, are made up of three quarks (anti-baryons are made up of three antiquarks). Proton consists of two upper quarks and one lower quark, and neutron consists of two lower quarks and one upper quark. And all mesons are made up of a pair of positive and negative quarks.

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