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Three antiquarks of different anticolors, giving an antibaryon with baryon number −1. The baryon number was defined long before the quark model was established, so rather than changing the definitions, particle physicists simply gave quarks one third the baryon number. Nowadays it might be more accurate to speak of the conservation of quark ...
Mesons named with the letter "f" are scalar mesons (as opposed to a pseudo-scalar meson), and mesons named with the letter "a" are axial-vector mesons (as opposed to an ordinary vector meson) a.k.a. an isoscalar vector meson, while the letters "b" and "h" refer to axial-vector mesons with positive parity, negative C-parity, and quantum numbers I G of 1 + and 0 − respectively.
Because quarks have a spin 1 / 2 , the difference in quark number between mesons and baryons results in conventional two-quark mesons being bosons, whereas baryons are fermions. Each type of meson has a corresponding antiparticle (antimeson) in which quarks are replaced by their corresponding antiquarks and vice versa.
These lists detail all known and predicted baryons in total angular momentum J = 1 / 2 and J = 3 / 2 configurations with positive parity. [5]Baryons composed of one type of quark (uuu, ddd, ...) can exist in J = 3 / 2 configuration, but J = 1 / 2 is forbidden by the Pauli exclusion principle.
Because mesons have integer spin (0 or 1) and are not themselves elementary particles, they are classified as "composite" bosons, although being made of elementary fermions. Examples of mesons include the pion, kaon, and the J/ψ. In quantum hadrodynamics, mesons mediate the residual strong force between nucleons.
Mesons are hadrons with zero baryon number. If the quark–antiquark pair are in an orbital angular momentum L state, and have spin S, then | L − S | ≤ J ≤ L + S, where S = 0 or 1, P = (−1) L+1, where the 1 in the exponent arises from the intrinsic parity of the quark–antiquark pair. C = (−1) L+S for mesons which have no flavor.
particles belong to the "pseudo-scalar" nonet of mesons which have spin J = 0 and negative parity, [9] [10] and η and η′ have zero total isospin, I, and zero strangeness, and hypercharge. Each quark which appears in an η particle is accompanied by its antiquark, hence all the main quantum numbers are zero, and the particle overall is ...
These include glueballs and hybrid mesons (mesons bound by excited gluons). Because mesons have an even number of quarks, they are also all bosons, with integer spin, i.e., 0, +1, or −1. They have baryon number B = 1 / 3 − 1 / 3 = 0 . Examples of mesons commonly produced in particle physics experiments include pions and kaons.