All quarks are described in a similar way by electroweak and quantum chromodynamicsbut the bottom quark has exceptionally low rates of transition to lower-mass quarks. The bottom quark is also notable because it is a product in almost all top quark decays, and is a frequent decay product of the Higgs boson. The bottom quark was first described theoretically in by physicists Makoto Kobayashi and Toshihide Maskawa to explain CP violation.
Color charge is a property of quarks and gluons that is related to the particles' strong interactions in the theory of quantum chromodynamics QCD. The "color charge" of quarks and gluons is completely unrelated to the everyday meaning of color. The term color and the labels red, green, and blue became popular simply because of the loose analogy to the primary colors.
Most of the mass of ordinary matter comes from two hadrons, the proton and the neutron. Hadrons are categorized into two families: baryonsmade of an odd number of quarks — usually three quarks — and mesonsmade of an even number of quarks—usually one quark and one antiquark. Almost all "free" hadrons and antihadrons meaning, in isolation and not bound within an atomic nucleus are believed to be unstable and eventually decay break down into other particles.
The energy appears in some other form, perhaps as a different particle and its antiparticle and their energyperhaps as many mesons, perhaps as a single neutral boson such as a Z 0 boson. The produced particles may be any combination allowed by conservation of energy and momentum and of all the charge types and other rules. We define the fermions that are common in our Universe as matter and their antiparticles as antimatter. The asymmetry of the Universe between these two classes of particles is a deep puzzle for which we are not yet completely sure of an explanation.
The up quark or u quark symbol: u is the lightest of all quarksa type of elementary particleand a major constituent of matter. It, along with the down quarkforms the neutrons one up quark, two down quarks and protons two up quarks, one down quark of atomic nuclei. The antiparticle of the up quark is the up antiquark sometimes called antiup quark or simply antiupwhich differs from it only in that some of its properties, such as charge have equal magnitude but opposite sign.
The down quark or d quark symbol: d is the second-lightest of all quarksa type of elementary particleand a major constituent of matter. Together with the up quarkit forms the neutrons one up quark, two down quarks and protons two up quarks, one down quark of atomic nuclei. The antiparticle of the down quark is the down antiquark sometimes called antidown quark or simply antidownwhich differs from it only in that some of its properties have equal magnitude but opposite sign.
In particle physicsthe quark model is a classification scheme for hadrons in terms of their valence quarks —the quarks and antiquarks which give rise to the quantum numbers of the hadrons. The quark model underlies "flavor SU 3 "or the Eightfold Waythe successful classification scheme organizing the large number of lighter hadrons that were being discovered starting in the s and continuing through the s. It received experimental verification beginning in the late s and is a valid effective classification of them to date. The model was independently proposed by physicists Murray Gell-Mann who dubbed them "quarks" in a concise paper, and George Zweig  who suggested "aces" in a longer manuscript.
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Quarks combine to form composite particles called hadronsthe most stable of which are protons and neutronsthe components of atomic nuclei. Quarks have various intrinsic propertiesincluding electric chargemasscolor chargeand spin. They are the only elementary particles in the Standard Model of particle physics to experience all four fundamental interactionsalso known as fundamental forces electromagnetismgravitationstrong interactionand weak interactionas well as the only known particles whose electric charges are not integer multiples of the elementary charge. There are six types, known as flavorsof quarks: updownstrangecharmbottomand top.