pionnets

Pionnets are a type of particle in particle physics. They are classified as mesons, which means they are composite particles made up of a quark and an antiquark. Specifically, pions are the lightest known mesons. There are three types of pions: the positive pion (π⁺), the negative pion (π⁻), and the neutral pion (π⁰).

The charged pions, π⁺ and π⁻, are antiparticles of each other. They are composed of an up quark and a down antiquark, or a down quark and an up antiquark, respectively. The neutral pion, π⁰, is its own antiparticle and is composed of a combination of up quark and up antiquark, or down quark and down antiquark.

Pions were first discovered in cosmic rays in 1947 by Cecil Powell and his colleagues. They play a crucial role in the nuclear force, the force that binds protons and neutrons together in the atomic nucleus. Although the strong nuclear force is the fundamental interaction, pions are mediators of the residual strong force that operates between nucleons.

The charged pions have a mass of about 139.6 MeV/c² and decay relatively quickly, typically into a muon and a muon neutrino. The neutral pion is slightly lighter, with a mass of about 135.0 MeV/c², and decays even faster, usually into two photons. The study of pion properties and interactions has been fundamental to the development of quantum field theory and our understanding of the subatomic world.