In particle physics, a particle is a fundamental unit of matter or energy that exhibits certain properties and interacts with other particles. These particles are the building blocks of the universe, and the study of their behavior and interactions forms the basis of particle physics.
Particles in particle physics can be divided into two main categories: elementary particles and composite particles.
Elementary Particles: These are the fundamental particles that are not known to have any substructure or internal constituents. According to the Standard Model of particle physics, which is the prevailing theory describing particle interactions, there are several types of elementary particles:
Quarks: Quarks are fundamental particles that combine to form protons and neutrons, which are the building blocks of atomic nuclei. There are six types of quarks: up, down, charm, strange, top, and bottom.
Leptons: Leptons are another type of elementary particles. They include electrons, muons, and tau particles, as well as their corresponding neutrinos. Electrons are familiar particles that orbit around atomic nuclei, while the other leptons are heavier and unstable.
Gauge Bosons: Gauge bosons are particles that mediate fundamental forces. For example, photons are the mediators of the electromagnetic force, while W and Z bosons mediate the weak nuclear force. Gluons mediate the strong nuclear force, which holds atomic nuclei together.
Higgs Boson: The Higgs boson is a particle that was discovered at the Large Hadron Collider (LHC) in 2012. It interacts with other particles to give them mass.
Composite Particles: These particles are made up of combinations of elementary particles. The most familiar composite particles are protons and neutrons, which are composed of quarks held together by the strong nuclear force. Protons and neutrons are collectively known as nucleons and are found in atomic nuclei.
Particles in particle physics can be studied and observed using high-energy particle accelerators and detectors. By colliding particles together at high speeds, scientists can create conditions similar to those in the early universe and study the properties and interactions of particles at extremely small scales.
It's worth noting that the field of particle physics is a dynamic and evolving area of scientific research. New particles and phenomena may be discovered as our understanding of the universe continues to advance.