Let's define and classify these terms:
Bosons: Bosons are a class of particles that obey Bose-Einstein statistics. They have integer values of spin (0, 1, 2, etc.). Bosons include particles like photons (the particles of light), gluons (particles that mediate the strong force), and the W and Z bosons (particles involved in weak interactions). Bosons can occupy the same quantum state simultaneously, leading to phenomena such as Bose-Einstein condensation.
Fermions: Fermions are particles that obey Fermi-Dirac statistics. They have half-integer values of spin (1/2, 3/2, etc.). Fermions include particles like electrons, protons, and neutrons. The Pauli exclusion principle states that no two fermions can occupy the same quantum state simultaneously, which gives rise to the stability of matter.
Leptons: Leptons are a group of fundamental particles that are classified as fermions. They do not interact via the strong nuclear force. The electron, muon, and tau particles, along with their corresponding neutrinos (electron neutrino, muon neutrino, and tau neutrino), are examples of leptons. Leptons are not composed of smaller particles.
Hadrons: Hadrons are particles that are composed of quarks. Quarks are elementary particles that are fermions. Hadrons can be classified into two main categories: baryons and mesons.
a) Baryons: Baryons are a class of hadrons that consist of three quarks. Protons and neutrons, which are the building blocks of atomic nuclei, are examples of baryons. Baryons are fermions since they are composed of three quarks.
b) Mesons: Mesons are a class of hadrons that consist of a quark and an antiquark. They are bosons since they are composed of an even number of quarks. Examples of mesons include the pion and the kaon.
It's important to note that both leptons and hadrons are fermions, but the distinction lies in their composition. Leptons are fundamental particles, while hadrons are composite particles made up of quarks.
This classification provides a basic understanding of the different types of particles in particle physics and their key properties.