Ad
related to: baryon number of mesons book review
Search results
Results From The WOW.Com Content Network
It is defined as = (¯), where is the number of quarks, and ¯ is the number of antiquarks. Baryons (three quarks) have a baryon number of +1, mesons (one quark, one antiquark) have a baryon number of 0, and antibaryons (three antiquarks) have a baryon number of −1.
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.
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.
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.
[4] [5] [b] The discovery of new mesons and baryons continued through the 1950s; the number of known "elementary" particles ballooned. Physicists were interested in understanding hadron-hadron interactions via the strong interaction.
Mesons are made of a valence quark–antiquark pair (thus have a baryon number of 0), while baryons are made of three quarks (thus have a baryon number of 1). This article discusses the quark model for the up, down, and strange flavors of quark (which form an approximate flavor SU(3) symmetry). There are generalizations to larger number of flavors.
A proton, the only baryon stable in isolation, has two up quarks and one down quark, confined via the exchange of gluons.. Baryons are composite particles made of three quarks, as opposed to mesons, which are composite particles made of an equal number of quarks and antiquarks.
The baryon number of all mesons is, indeed, zero. The square roots in the quark content are just normalization factors . MuDavid ( talk ) 14:58, 8 June 2010 (UTC) [ reply ]