Hadrons Hadrons - the largest class of elementary particles.All hadrons are involved in strong interactions, as in all other types of interactions.These particles are composed of quarks, the most famous of them - the neutron and proton.Hadrons consisting of a quark and an antiquark, called mesons.Baryons - hadrons, which include the three quarks.

hadrons also include K-mesons, hyperons and other particles.All hadrons except neutrons are unstable, they disintegrate.Resonance called hadrons decay by the strong interaction.Quarks and hadrons may participate in all interactions, leptons do not participate in the strong interaction.

fundamental particles



In addition, there are structureless hadron particles - leptons, qua
rks, photons and others.They are called fundamental, among them the well known 6 quarks and 6 leptons.They all have spin ½ fermions and are fundamental, they are divided into three groups - generation in each of the two leptons and two quarks.

leptons



leptons is a group of point structureless particles that do not participate in the strong interaction.There are three pairs of leptons: the electron and the electron neutrino, muon and muon neutrino, and the tau lepton and tau lepton-neutrino.The reason for the existence of three pairs of leptons unclear.

Each pair is characterized by its lepton quantum number, which is also called lepton flavor.Lepton quantum numbers (flavor) are stored in all of the observed response and decay.At the electron and the electron neutrino, muon and muon neutrino, tau lepton and tau neutrino, this number is one, have antileptons signs lepton numbers opposite.

stable electron and neutrino, tau lepton and muon is unstable, they decay into lighter particles.The muon, electron and tau lepton have the same negative charge, but their weight is different.Neutrinos are electrically neutral and have zero or very low mass.

Fermions



Particles are first generation quarks u or d, as well as the electron.Among them is the entire observable matter, quarks u or d are part of the nucleons of the nuclei of atoms consist of nucleons.The atoms form a nucleus with electrons in orbits.Fermions have half-integer spin (1/2, 3/2, 5/2) and obey Fermi-Dirac statistics, according to which a state with a certain set of quantum numbers can be only one fermion type.

Bosons



there are particles with spin 1 is the photon, gluons, bosons, Z and W, as well as the spin-2 (graviton), they are called fundamental bosons.Bosons act as vectors of interaction.The particles are bosons are exchanged in the course of various fundamental interactions - strong, weak, electromagnetic and gravitational.