baryon number

physics

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June 24, 2026

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Baryon number is a property of subatomic particles, specifically hadrons, which are composed of quarks. Baryons, such as protons and neutrons, are made of three quarks and have a baryon number of 1. Antibaryons have a baryon number of -1, while mesons and leptons have a baryon number of 0.12

A fundamental principle in physics is the law of baryon conservation, which states that the total baryon number in an isolated system remains constant during reactions or decays. This law explains why protons are stable, as they cannot decay into lighter particles with a baryon number of 0. While baryon number is conserved in most interactions, it's theorized that at extremely high energies, such as those in the early universe, this conservation may be violated.134

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baryon
Baryons are characterized by a baryon number, B, of 1. Their antiparticles, called antibaryons, have a baryon number of −1. An atom containing, for example, one proton and one neutron (each with a baryon number of 1) has a baryon number of 2. In addition to their differences in composition,…
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Baryons are characterized by a baryon number, B, of 1. Their antiparticles, called antibaryons, have a baryon number of −1. An atom containing, for example, one proton and one neutron (each with a baryon number of 1) has a baryon number of 2. In addition to their differences in composition,…
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subatomic particle
Baryons and mesons
…baryons are characterized by a baryon number, B, of 1; antibaryons have a baryon number of −1; and the baryon number of the mesons, leptons, and messenger particles is 0. Baryon numbers are additive; thus, an atom containing one proton and one neutron (each with a baryon number of 1)…
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…baryons are characterized by a baryon number, B, of 1; antibaryons have a baryon number of −1; and the baryon number of the mesons, leptons, and messenger particles is 0. Baryon numbers are additive; thus, an atom containing one proton and one neutron (each with a baryon number of 1)…
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cosmology
Matter-antimatter asymmetry
…physics, because the net “baryon” number (for present purposes, protons and neutrons minus antiprotons and antineutrons) was thought to be a conserved quantity. Therefore, once it exists, it always exists, into the indefinite past and future. Developments in particle physics during the 1970s, however, suggested that the net baryon…
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…physics, because the net “baryon” number (for present purposes, protons and neutrons minus antiprotons and antineutrons) was thought to be a conserved quantity. Therefore, once it exists, it always exists, into the indefinite past and future. Developments in particle physics during the 1970s, however, suggested that the net baryon…
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symmetry
Such an internal symmetry is baryon number, which is a property of a class of particles called hadrons. Hadrons with a baryon number of zero are called mesons, those with a number of +1 are baryons. By symmetry there must exist another class of particles with a baryon number of…
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Such an internal symmetry is baryon number, which is a property of a class of particles called hadrons. Hadrons with a baryon number of zero are called mesons, those with a number of +1 are baryons. By symmetry there must exist another class of particles with a baryon number of…
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