In the standard model theory of modern particle physics, baryon refers to a composite particle composed of three quarks (or three antiquarks). In this theory, it is a kind of hadron. It is worth noting that baryon is not an elementary particle because it belongs to a composite particle. The most common baryons are protons and neutrons, which constitute the nucleus of everyday matter and are called nucleons together with antiprotons and antineutrons.

Chinese name: baryon mbth: baryon discipline: physics example: proton and neutron pinyin of nuclear: composition of baryon: introduction of three quarks and baryons, baryon family, baryon (baryon) hadron whose spin is a semi-odd multiple of H, their statistical properties belong to fermion. The most familiar baryons are protons and neutrons, and there are other particles such as λ, σ, ξ, ω, etc. Its mass exceeds that of protons and neutrons, so it is also called hyperon. For all baryons, you can define a baryon number b, the baryon number is+1 and the anti-baryon number is-1. The baryon number is conserved under all interactions, and other baryons except protons will eventually decay into protons, thus ensuring the stability of protons. It has been found that all kinds of baryons are composed of three quarks, such as p=(uud), n=(udd), λ o = (UDS), σ+= (UUS), ξ-= (DSS), ω = (SSS) and so on. The experimental evidence of the existence of charmed baryons such as λ c+(UDC) and σ c+(UUC) of the fourth quark is also found. Among other baryons, there are particles heavier than these two kinds of particles, the so-called hyperons. Baryon is called baryon because its mass is relatively heavier than lepton and meson in between. Baryons are fermions with strong interaction, that is, they obey Fermi-Dirac statistics and Pauli exclusion principle, and they participate in strong interaction through the quarks that make them up. At the same time, they also participate in weak interaction and gravity. Charged baryons also participate in electromagnetic force. Baryon and meson composed of a quark and an antiquark are called hadrons. Hadron is a general term for all strongly interacting particles. Proton is the only independent and stable baryon. Neutrons are unstable and will decay if they do not form nuclei with other neutrons or protons. Baryon family Baryon family δ baryon (δ, δ, δ, δ) consists of upper quarks and lower quarks and decays into π mesons and a proton or a neutron. λ baryon (λ, λ c) consists of an upper quark, a lower quark, an attractive quark or a strange quark. The discovery of electrically neutral λ baryon indicates the existence of strange quarks for the first time. σ baryon (σ, σ, σ) consists of a singular quark and two upper quarks or lower quarks or an upper quark and a lower quark. The electrically neutral σ baryon is the same as the electrically neutral λ baryon, so it decays faster than other σ baryons. ξ baryon (ξ, ξ) consists of two strange quarks and an upper quark or a lower quark. The electrically neutral ξ baryon (composed of an upper quark and two odd quarks) decays into an electrically neutral λ baryon and an electrically neutral π meson, and the latter rapidly decays into an electron and a positron, which annihilate each other, so the whole process looks as if the electrically neutral ξ baryon decays into an electrically neutral λ baryon and a γ ray. The electronegative ω baryon (ω) consists of three strange quarks. Theorists first predicted its existence, quality and decay results. It was discovered through these predictions and its decay results, so its discovery is an important achievement of quark theory.