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In particle physics, a hadron is a subatomic particle which experiences the strong nuclear force. In current quark model s, hadrons are composed of fermions called quarks and antiquarks and of bosons called gluons. The gluons mediate the color force that binds the quarks together. Hadrons are composite particles bound together the color interaction, and thus are somewhat analogous to atoms, in which particles are bound together by the electromagnetic interaction.Hadrons are further classified by their spin and quark content.
- Baryons are composed of three quarks or three anti-quarks and have half-odd-integral spin, i.e. they are fermions. They include the nucleons (the proton and the neutron), which are part of normal atomic nuclei, and particles such as the hyperons (e.g. the Δ, Λ, Σ, Ξ, and Ω), which are generally heavier than nucleons, short-lived, and do not normally appear in atomic nuclei.
- MesonIn particle physics, a meson is a strongly interacting boson, that is, it is a hadron with integral spin. In the Standard Model, mesons are composite (non-elementary) particles composed of an even number of quarks and antiquarks. Until the discovery of ths are composed of a quark and an anti-quark and have integral spin, i.e. they are bosons. They include the pionIn particle physics, pion (short for 'pi meson') is the collective name for three subatomic particles discovered in 1947: π0, π+ and π−. Pions are the lightest mesons. Basic properties Pions have zero spin and are composed of first generatis, the kaonThe neutral Kaons represent symmetric and antisymmetric mixtures of the quark combinations down-antistrange and antidown-strange. The charged kaons are mesons which have a quark composition of up-antistrange for the positive kaon and antiup-strange for ths, the rho s, the omega s, and many other types of mesons.
- Exotic hadrons do not have the quark numbers of either ordinary baryons or mesons.
- Exotic baryonIn particle physics, an exotic baryon is a baryon (a strongly interacting fermion) composed of more than three quarks. Currently, only one type of exotic baryon, the pentaquark, is known. It consists of four quarks and one antiquark. The composition of exs are composed of more than three quarks (or anti-quarks) odd in number. The first such particles, pentaquarkA pentaquark is a subatomic particle consisting of a group of five quarks (compared to three quarks in normal baryons and two in mesons), or more specifically four quarks and one anti-quark. Hence it has baryon number 1. It has therefore been assigned a ns, are thought to have been discovered recently. They have four quarks and one anti-quark.
- Exotic mesonIn particle physics, an exotic meson is a meson (a strongly interacting boson) that does not contain exactly one valence quark- antiquark pair. Currently, there is experimental evidence for only one type of exotic meson, the tetraquark. It consists of twos contain more than one valence quark-antiquark pair. Recently there has been some evidence for the tetraquarkA tetraquark is a subatomic particle composed of four quarks. One of the most bizarre properties of quarks is that they can never exist individually. They always manifest themselves in groups such as groups of two ( mesons) or groups of three ( protons, n, which consists of two valence quark-antiquark pairs.
- Hybrid meson s consist of at least one valence quark-antiquark pair and at least one real (not virtual) gluon.
- Glueballs contain no valence quarks at all, being composed solely of gluons. These states mix strongly with ordinary mesons and are extremely difficult to identify.
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Hadron
