baryon (bâr`ēŏn') [Gr.,=heavy], class of elementary particles elementary particles, the most basic physical constituents of the universe.

Basic Constituents of Matter

Molecules are built up from the atom , which is the basic unit of any chemical element .
..... Click the link for more information. that includes the proton proton, elementary particle having a single positive electrical charge and constituting the nucleus of the ordinary hydrogen atom. The positive charge of the nucleus of any atom is due to its protons.
..... Click the link for more information. , the neutron neutron, uncharged elementary particle of slightly greater mass than the proton . It was discovered by James Chadwick in 1932. The stable isotopes of all elements except hydrogen and helium contain a number of neutrons equal to or greater than the number of protons.
..... Click the link for more information. , and a large number of unstable, heavier particles, known as hyperons. From a technical point of view, baryons are strongly interacting fermions; i.e., they experience the strong nuclear force force, commonly, a "push" or "pull," more properly defined in physics as a quantity that changes the motion, size, or shape of a body. Force is a vector quantity, having both magnitude and direction.
..... Click the link for more information. and are described by the Fermi-Dirac statistics, which apply to all particles obeying the Pauli exclusion principle exclusion principle, physical principle enunciated by Wolfgang Pauli in 1925 stating that no two electrons in an atom can occupy the same energy state simultaneously.
..... Click the link for more information. . All members of the baryon family of particles adhere to the law of conservation of baryon family number (see conservation laws conservation laws, in physics, basic laws that together determine which processes can or cannot occur in nature; each law maintains that the total value of the quantity governed by that law, e.g., mass or energy, remains unchanged during physical processes.
..... Click the link for more information. , in physics); the baryon family number is +1 for ordinary baryons and −1 for antibaryons (see antiparticle antimatter, composed of atoms made up of antiprotons and antineutrons in a nucleus surrounded by positrons. A very simple type of "atom" incorporating antiparticles is positronium, a brief pairing of a positron and an electron that may occur before their annihilation.
..... Click the link for more information. ). In any particle interaction, the sum of the baryon family numbers of the interacting particles must equal the sum for the resulting particles. In reactions involving only nucleons, this law requires that the total number of nucleons be the same before and after the reaction. In addition to the nucleons (protons and neutrons), other members of the baryon family include the lambda, sigma, delta, xi, and N particles, as well as a series of higher-mass recurrences of each of these particles. These recurrences may be considered excited states of the lowest-mass member of the series.

baryon

Any member of one of two classes of hadrons. Baryons are heavy subatomic particles made up of three quarks. They are characterized by a baryon number, B, of 1, and have half-integer spin values. Their antiparticles (see antimatter), called antibaryons, have a baryon number of −1. Both protons and neutrons are baryons.

baryon (redirected from antibaryon)

Basic Constituents of Matter

baryon

baryon
(redirected from antibaryon)