Baryons have units {quark}|. Quarks have no internal structure, have diameter 10^-15 meters, and feel all forces.
types
Up quark has lowest mass, 2 MeV, one-ninth proton mass and nine times electron mass.
Down quark is slightly heavier, 5 MeV, 14 times electron mass.
Strange quark has one-third proton mass, 95 MeV, 1.5 times muon mass. Strange quark is 20 times bigger than up or down quark. Strange quarks are in kaons.
Charmed quark has 1.5 times proton mass, 1.25 GeV, 15 times muon mass. Charmed quarks are in J (psi) particles.
Bottom quark has one-third proton mass, 4.2 GeV, 2.7 times tau mass. Bottom quark is 600 times bigger than up or down quark. Bottom quarks are in B mesons.
Top quark [1995] has 1.5 times proton mass, 171 GeV, 99 times tau mass. Top quark has same mass as osmium.
flavor
Quarks have six flavors: upness, downness, strangeness, charm, topness, and bottomness.
charge
Up, charmed, and top quarks have charge +2/3. Down, strange, and bottom quarks have charge -1/3. The weak interaction has a quantum number T (weak isopin), which has three components. The third component T3 is conserved in all weak interactions (weak isospin conservation law) and in all interactions.
Fermions have spin 1/2. If spin direction and the direction of motion are the same, fermion helicity is right-handed, and spin is counterclockwise +1/2. If spin direction and the direction of motion are the opposite, fermion helicity is left-handed, and spin is clockwise -1/2. Massless particles move at light speed, so all observers see the same helicity. Observers can move faster than massive particles, so such observers see helicity change.
Particles have transformations, some of which (chiral transformations) can be different for left-handed or right-handed particle properties. For example, left-handed fermions have weak interactions, but right-handed fermions do not. Most transformations (vector transformations) are the same for both left-handed and right-handed properties.
Transformations can be symmetric or anti-symmetric, with parity even or odd, respectively. Most transformations involving left-handed and right-handed conserve parity (chiral symmetry), but weak interactions do not.
Left-handed fermions have spin -1/2, have negative chirality, have T = 1/2, are doublets with T3 = +1/2 or -1/2, and so have weak interactions. Right-handed fermions have spin +1/2, have positive chirality, have T = 0, are singlets with T3 = 0, and so never have weak interactions.
Electromagnetism and the weak interaction interact (electroweak). Electromagnetism has electric charges. The weak interaction has gauge bosons W+, W-, and W0. The electroweak interaction has a weak hypercharge Yw that generates the U(1) group of the electroweak gauge group SU(2)xU(1). The (unobservable) gauge boson W0 interacts with weak hypercharge Yw to make (observable) Z gauge boson and photon. For left-handed quarks, Yw = +1/3 or -1/3. [In grand unified theories, weak hypercharge depends on the conserved X-charge and on baryon number minus lepton number: Yw = (5 * (B - L) - X) / 2.]
To make interactions renormalizable, a group of interactions must cancel all asymmetries (anomaly cancellation). The weak interaction has both charge and parity asymmetry, and does not conserve charge or parity, but the electroweak interaction cancels all asymmetries and conserves charge-parity-time (CPT conservation) together ['t Hooft and Veltman, 1972]. This requires that electric charge Q be related to weak isospin T3 and weak hypercharge Yw: Q = T3 + Yw / 2. For left-handed quarks, T3 = +1/2 or -1/2, and Yw = +1/3 or -1/3, so Q = +2/3 or -1/3.
isospin
Quarks are fermions. Up, charmed, and top quarks have weak-isospin third component +1/2. Down, strange, and bottom quarks have weak-isospin third component -1/2. Quarks have no right-handed weak-isospin components.
pairs
Six quarks have three pairs: up and down {up quark} {down quark}, strange and charmed {strange quark} {charmed quark}, and top and bottom {top quark} {bottom quark}.
lifetime
Up quark has infinite lifetime, because it cannot decay to anything. Other quarks can decay to lower-mass quarks. For quark pairs, one can change to the other by emitting W particle or Z particle.
distance
After distance, strong nuclear force stays constant with distance. Inside distance, quarks move freely. After distance, quarks have constant force between them, so they cannot separate. Quarks must be in mesons or baryons. Strong nuclear force makes quarks orbit in shells at relativistic speed.
Perhaps, empty space superconducts color charge and can contain color-charge flux as discrete quanta. Strings between particles are fundamental with derived fields, as in string theory, or color-charge field is fundamental with derived space structure, as in quantum chromodynamics.
leptons
Quarks and leptons are similar. Both are point-like, pair, and have six types.
neutron magnetic moment
Quarks can explain the magnetic moment that zero-charge neutrons have, because quarks have charges.
Quarks have property that uses red, green, or blue {color charge}| to show how they combine to make baryons and mesons, which have no color.
Quark types have one of six properties {flavor, quark}|: upness, downness, strangeness, charm, topness, and bottomness.
5-Physics-Matter-Particle-Subatomic-Fermion
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Date Modified: 2022.0225