Knowra Baryon number Baryon number Baryon number is a quantum number equal to the number of baryons minus antibaryons in a system. It is conserved in most observed particle interactions, though some theories and nonperturbative processes allow its violation.
Baryon : A hadron made of three valence quarks, such as a proton or neutron. Each baryon contributes +1 to the system’s baryon number.
Hadron : A composite particle made of quarks held together by the strong interaction. Baryons are one class of hadron, distinguished from mesons by their quark content.
Proton decay : A hypothetical decay of the proton into lighter particles, forbidden by baryon conservation in the Standard Model. Its observation would establish baryon-number violation and constrain theories beyond the Standard Model.
Lepton number : A quantum number that counts leptons minus antileptons in a system. It tracks leptonic content rather than baryonic content, though both are additive particle charges.
Antibaryon : A hadron composed of three valence antiquarks, corresponding to a baryon. Each antibaryon contributes −1, so pair production preserves the total.
Meson : A hadron composed of a quark and an antiquark. Mesons have baryon number zero, unlike baryons and antibaryons.
Neutron–antineutron oscillation : A hypothetical transition in which a neutron changes into its antiparticle. The transition changes baryon number by two units.
Strangeness : A flavor quantum number that counts strange antiquarks minus strange quarks. Unlike baryon number, strangeness can change in weak interactions.
Quark : An elementary fermion that carries color charge and combines with other quarks to form hadrons. Quarks carry baryon number +1/3, allowing composite hadrons’ numbers to be counted.
Lepton : An elementary fermion that does not participate in the strong interaction. Leptons carry no baryon number, even when reactions produce them alongside baryons.
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