Color singlet game

Choose two or three quarks or antiquarks, then select Check. Repeated selections are allowed. Remove individual particles to try another combination. Free play checks any of the three families; the quiz asks for meson, baryon, antibaryon, meson and baryon components in that order. Each round accepts one answer, then unlocks the next round. A wrong answer resets the streak. Changing mode or starting a new quiz starts a fresh game.

Color is a charge label. R, G and B do not describe visible light; barred symbols denote the corresponding anticolors. A matching selection is a basis component of a color singlet. It is not by itself the complete singlet quantum state.

A normalized meson color singlet is (|R R̄⟩ + |G Ḡ⟩ + |B B̄⟩) / √3. A normalized baryon color singlet is (|RGB⟩ + |GBR⟩ + |BRG⟩ − |RBG⟩ − |GRB⟩ − |BGR⟩) / √6. The corresponding antibaryon state is (|R̄ḠB̄⟩ + |ḠB̄R̄⟩ + |B̄R̄Ḡ⟩ − |R̄B̄Ḡ⟩ − |ḠR̄B̄⟩ − |B̄ḠR̄⟩) / √6. The three or six terms are orthogonal basis states, which explains the normalization factors.

The order of slots matters in these quantum expressions: the baryon sums have alternating signs. The game checks only whether the selected colors can occur in one of those terms, so rearranging a selection does not change its answer. It does not construct the superposition or calculate flavor, mass, binding energy or the full range of hadrons. More than three particles is outside this game, not a general prohibition in physics.

The small game state, including checked answers, is retained when local tool-state storage is enabled. Scores are reconstructed from those answers; this is a local learning exercise without a timer or online ranking.

Source: Harald Fritzsch, The history of QCD, CERN Courier (2012), for color indices and singlet states. Its historical discussion is not a statement about the current experimental status of exotic hadrons.