Quarkbinders: Quantum Chromodynamics / Strong Nuclear Force
Nuclear & Particle Physics arc, page 169 of 193. Back to The Pixelated Physics Universe
Who they are
Quarks come in threes, and never alone. Quarks carry a three-valued charge called colour, proposed in 1964–65 to save the Pauli principle. In 1973 Gross, Wilczek and Politzer found the strong force weakens at short distances, asymptotic freedom; at long range it confines quarks inside hadrons. Quarkbinders on a pixel-art unisex tee; equation, symbols and sources in the panel below.
Quarkbinders is a character of the Nuclear & Particle Physics arc: drawn in pixels, ruled by one piece of real physics, and never allowed to break it.
The physics
Baryons such as the proton are built from three quarks with three different colour charges, combined so that the whole is colourless. The strong coupling also gets weaker at high energies (asymptotic freedom), which is why quarks behave as almost free particles inside fast collisions.
$$ \begin{gathered} \lvert B\rangle \propto \varepsilon_{ijk}\,\lvert q^{i} q^{j} q^{k}\rangle \\ \alpha_s(Q^{2}) \approx \frac{12\pi}{(33 - 2n_f)\ln\!\left(Q^{2}/\Lambda_{\text{QCD}}^{2}\right)} \end{gathered} $$
| Symbol | Meaning | SI unit |
|---|---|---|
| $\varepsilon_{ijk}$ | Levi-Civita symbol over colour indices (antisymmetric colour singlet) | 1 |
| $q^{i}$ | quark with colour index i | — |
| $\alpha_s$ | strong coupling | 1 |
| $Q$ | momentum-transfer scale (often written in GeV, natural units with c = 1) | GeV/c |
| $n_f$ | number of active quark flavours | 1 |
| $\Lambda_{\text{QCD}}$ | QCD scale parameter (an energy scale, natural units) | GeV |
Sources
- Gell-Mann (1964) A schematic model of baryons and mesons, Phys. Lett. 8, 214
- Greenberg (1964) Spin and Unitary-Spin Independence in a Paraquark Model, PRL 13, 598
- Han & Nambu (1965) Three-Triplet Model with Double SU(3) Symmetry, Phys. Rev. 139, B1006
- Fritzsch, Gell-Mann, Leutwyler (1973) Advantages of the color octet gluon picture, Phys. Lett. B 47, 365
- Gross & Wilczek (1973) Ultraviolet Behavior of Non-Abelian Gauge Theories, PRL 30, 1343
- Politzer (1973) Reliable Perturbative Results for Strong Interactions?, PRL 30, 1346
- NobelPrize.org — The Nobel Prize in Physics 2004 (asymptotic freedom)
- NobelPrize.org — Murray Gell-Mann, Physics 1969, facts
- Encyclopaedia Britannica — Quantum chromodynamics
- PDG 2024 review — Quantum Chromodynamics
Crossovers
Quarkbinders meets Hadron Brawler (Strong Nuclear Force / Quantum Chromodynamics). Quarkbinders gives quarks their three colours. Hadron Brawler shows the result: the strong force grows with distance, so coloured quarks are only ever found inside colour-neutral hadrons.
Quarkbinders meets Tripla (Anomaly That Counts Colours). Tripla's pion decay to two photons counts the quark colours. The rate matches experiment for three colours, which backs Quarkbinders' charge.
Quarkbinders meets Thetarch (Θ⁺(1540) Pentaquark). Thetarch claimed five quarks bound together. Quarkbinders allows colour-neutral combinations beyond three, and later experiments did report other pentaquark states, but not Thetarch's.
Wear the lore
Concept keywords: Quantum Chromodynamics / Strong Nuclear Force, Quarkbinders, Nuclear & Particle Physics, physics lore, Pixelated Physics