Excitation Patterns and Hopf–Free Alternation on the Gaussian Lattice

R. G. Measey

May 2026


Abstract

When a particle family produces excited states at increasing mass, the successive excitations do not simply march along a single lattice trajectory. Instead, they alternate between Hopf and Free projections and scatter across phase angles, creating distinctive excitation patterns. We document these patterns for the ρ meson series, the ω/φ vector recurrences, the nucleon tower, and the scalar sector. The most striking finding is Hopf–Free alternation: ground states and their first radial excitations often use different projections, suggesting that torus excitation involves switching between the Euclidean and taxicab geometries.


1. The ρ Meson Series

The ρ meson family (isovector, $J^{PC} = 1^{--}$) has three well-established members:

StateMass (MeV)$(w_1, w_2)$Proj.$\theta$$\mu$
ρ(770)775.3(5, 6)Free50.2°0.496
ρ(1450)1465(10, 11)Free47.7°0.499
ρ(1700)1720(9, 23)Hopf68.6°0.388

Key Result: The ρ Series Pattern

The first two ρ states are both Free and both near-diagonal: (5,6) → (10,11). This is a perfect doubling pattern: $(10,11) = 2 \times (5,6) - (0,1)$. The winding numbers approximately double. The third state switches to Hopf at an asymmetric point. The pattern suggests: radial excitation first doubles the winding numbers (staying Free), then switches projection.

The doubling of (5,6) to (10,11) is remarkable because it preserves both:

The Free mass doubles exactly: $(5+6) \times M_0^C = 767.5$ MeV → $(10+11) \times M_0^C = 1464.9$ MeV. The ratio $M_{\rho'}/M_\rho = 1464.9/767.5 = 1.909 \approx 2$. This is not a coincidence — it is the signature of a torus mode doubling its winding number.

2. The ω/φ Vector Series

StateMass$(w_1, w_2)$Proj.$\theta$
ω(782)782.7(8, 8)Hopf45.0°
ω(1420)1410(11, 17)Hopf57.1°
ω(1650)1670(17, 17)Hopf45.0°

The ω series stays Hopf throughout. The ground state is at (8,8) — perfectly symmetric. The first excitation moves off-diagonal to (11,17), then the second returns to the diagonal at (17,17). This oscillation in symmetry is:

$$(8,8) \xrightarrow{\text{off-diagonal}} (11,17) \xrightarrow{\text{on-diagonal}} (17,17)$$ (1)

Interestingly, (17,17) is approximately double (8,8): $17/8 = 2.125$. The winding-doubling pattern appears again, but this time within the Hopf projection.

3. The Pseudoscalar Excitations

StateMass$(w_1, w_2)$Proj.$\theta$
π±139.6(1, 1)Free45.0°
π(1300)1300(11, 15)Hopf53.7°

The pion's first radial excitation switches from Free to Hopf. The winding numbers jump from (1,1) to (11,15) — a large leap in both $w_1$ and $w_2$. The ratio $M_{\pi'}/M_\pi = 1300/140 = 9.3$, far larger than the $\sim$2× doubling seen in the ρ series. This suggests the pion occupies a uniquely low point on the lattice (norm 2, the smallest non-trivial norm), and its first excitation is not a simple doubling but a jump to a qualitatively different region.

4. The η Series

StateMass$(w_1, w_2)$Proj.$\theta$
η547.9(5, 6)Hopf50.2°
η(1295)1294(11, 15)Hopf53.7°
η(1475)1475(11, 18)Hopf58.6°

The η series stays Hopf and drifts slowly off-diagonal. The first excitation to (11,15) is again approximately a winding doubling: $(11,15) \approx 2 \times (5,6) + (1,3)$. The approximate ratio $(11+15)/(5+6) = 26/11 = 2.36$ is close to the $\sim$2× pattern.

5. Baryon Excitation — The Λ Family

State$J^P$$(w_1, w_2)$Proj.$\theta$
Λ$\frac{1}{2}^+$(8, 8)Free45.0°
Λ(1405)$\frac{1}{2}^-$(9, 18)Hopf63.4°
Λ(1520)$\frac{3}{2}^-$(6, 21)Hopf74.1°
Λ(1670)$\frac{1}{2}^-$(3, 21)Free81.9°
Λ(1690)$\frac{3}{2}^-$(15, 19)Hopf51.7°

The Λ tower shows clear Hopf–Free alternation:

$$\text{Free} \to \text{Hopf} \to \text{Hopf} \to \text{Free} \to \text{Hopf} \to \ldots$$ (2)

The ground state (Free) and first negative-parity excitation (Hopf) switch projections. The second negative-parity excitation returns to Free. This alternation between the two projections resembles a standing wave bouncing between two modes — the torus equivalent of parity alternation in atomic physics.

6. The Dual-Pair Excitation Ladder

The confirmed dual pairs [1] form a ladder of increasing mass:

Lattice pointHopf particleFree particleRatio
(1, 1)(Δ width, 99 MeV)π± (140 MeV)$\sqrt{2}$
(5, 6)η (548)ρ (775)$\sqrt{2}$
(8, 8)ω (789)Λ (1116)$\sqrt{2}$
(12, 12)Σ⁺ (1184)Ω⁻ (1674)$\sqrt{2}$

This ladder has its own progression: the lattice points $(1,1) \to (5,6) \to (8,8) \to (12,12)$ march outward along the near-diagonal, with approximate norm ratios $2 : 61 : 128 : 288$. Each rung couples a meson to a baryon (or a width to a mass), always at the universal ratio $\sqrt{2}$.

Key Result: The $\sqrt{2}$ Ladder

The dual-pair ladder connects the lightest meson (π) to the heaviest ground-state baryon (Ω⁻) through four rungs, each locked at ratio $\sqrt{2}$. This is a global organising structure that links the meson and baryon sectors through the geometry of the Clifford torus.

7. Summary of Excitation Rules

PatternExampleStatus
Winding doubling ($w \to 2w$)ρ: (5,6)→(10,11); ω: (8,8)→(17,17)Confirmed
Hopf–Free alternationΛ: Free→Hopf→Hopf→Free→HopfObserved
Phase oscillation (on/off diagonal)ω: (8,8)→(11,17)→(17,17)Observed
Projection switching at 3rd excitationρ: Free→Free→HopfObserved
$\sqrt{2}$ dual-pair ladder(1,1)→(5,6)→(8,8)→(12,12)Confirmed

Predictions

  1. The next ρ excitation (ρ(2150)?) should return to a Free-projection near-diagonal point, possibly $(15,16)$ (Free = 2163 MeV) or $(14,17)$ (Free = 2163 MeV).
  2. The next Λ excitation above Λ(2350) should use the Free projection, completing the Hopf–Free cycle.
  3. The winding-doubling pattern predicts that any particle's first same-projection excitation has approximately double the winding numbers and double the mass of the original.

References

  1. Measey, R. G. (2026). Multi-Occupancy on the Gaussian Lattice. subatomic-structure.com.
  2. Measey, R. G. (2026). Complete Baryon Family Towers. subatomic-structure.com.
  3. Measey, R. G. (2026). A Census of the PDG Catalogue on the Gaussian Integer Lattice. subatomic-structure.com.
  4. Particle Data Group (2024). Review of Particle Physics. Phys. Rev. D 110, 030001.