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Boundary Coherence Theory · Paper 2 · v1.0 · 2026

What Is a Particle?

Quantitative Results — Zero Free Parameters
Ian Saunders · Perth, Australia
Foundational note
All headline results below are geometry-first consequences of the BCT ontology. They follow from boundary structure, admissibility constraints, and closure geometry rather than fitted particle parameters, force laws, or field postulates.
Derivation spine
Paper 2 does not assign properties to particles. It derives particle properties by a fixed method: first identify which localized boundary topologies are admissible, then compute the curvature inventory those topologies force, then read the result in projection as charge, mass, spin, generations, and particle language.
§1 — Ontological Primitive
What Is a Particle?
A particle is not a point object. It is a finite boundary vortex: integer tangential winding around a stored-curvature core, with radius bounded below by the healing length $R \ge \ell_m$. Charge is winding. Mass is stored curvature. Inertia is the cost of redistributing that curvature. In BCT, matter and radiation are not different substances: matter stores curvature in a persistent vortex; radiation transports curvature through a propagating boundary mode.
Winding (Charge)  SC
Integer winding number
$$q = \frac{1}{2\pi}\oint_\gamma \nabla\theta \cdot d\ell \;\in\; \mathbb{Z}$$
Single-valuedness of $\theta$ forces $q$ to be an integer. Winding cannot change continuously — it can only jump. This is why charge is discrete and conserved without being postulated.
Stored Curvature (Mass)  SC
Curvature inventory
$$C_{\mathrm{total}} = \int_{\partial\Omega} \!\!\left(|\nabla\xi|^2 + (\nabla^2\xi)^2\right) dS$$
Projected mass relation
$$m_{\mathbb{R}^3} \propto C_{\mathrm{total}}$$
Mass is not assigned by fiat. It is the curvature inventory of an extended boundary structure. Inertia is the cost of reorganising that curvature under the impedance law — no separate law of inertia required.
Finite Core (No Point Particles)  NG
Healing-length floor
$$\Theta(x) \ge \ell_m > 0 \quad \forall\, x \in \partial\Omega$$
The admissibility constraint $\ell_m > 0$ excludes zero-radius cores on two independent grounds. Point particles are not suppressed — they are structurally inadmissible. UV divergences do not arise; they were never possible.
Particle identity — three structural facts
Charge is winding.   Mass is stored curvature.   Inertia is redistribution cost.   The electron, muon, and tau are not separate primitives — they are the first three admissible eigenmodes of one monocore topology. The fourth mode is geometrically inadmissible.


§ — Channel Saturation and Generation Termination
The Three Charged Leptons
The monocore termination patch has two independent tangential closure channels. Each eigenmode beyond the first adds one reversal strip engaging one channel. At n = 3 both channels saturate — a fourth eigenmode is geometrically inadmissible, not suppressed.
Lepton reading key  SC
Monocore means one winding centre: the charged-lepton topology. CAP is the binary core-termination orientation, read in projection as spin-like doubling. Reversal strip is an internal phase-reversal band that adds curvature inventory to the same monocore. The electron, muon, and tau are not three different particle primitives. They are three admissible internal curvature states of the same monocore topology: the topology is shared; the mass changes because the internal curvature inventory changes.
Electron  ·  n = 1  ·  Zero reversal strips  EI
Topological ground state
$C_1$ — minimum admissible curvature inventory
$m_e = 0.511\,\text{MeV}$
Single empirical anchor: $\ell_m = \ell_P$
Candidate formula [DR]
$\dfrac{m_e}{m_P} = \exp\!\left(-\dfrac{3\alpha^{-1}}{8}\right)$  prefactor branch open
What this fixes: the electron is the zero-strip ground state, so it sets the reference curvature inventory $C_1$. It is not fitted to the muon or tau. Once $C_1$ is selected, the next two cards are ratios measured against this baseline.
Muon  ·  n = 2  ·  One reversal strip  SC
Mode count [SC]
$5 = d_T + d_T d_V + d_V$
Node cost [SC]
$\dfrac{\Delta C_{\text{node}}}{C_1} = 5 \times \dfrac{\pi^2}{d} \times \dfrac{4\pi}{3} = \dfrac{20\pi^3}{3}$
How the ratio is built: the muon is the first excited monocore state. It is not assigned an arbitrary extra strip: the first available tangential closure channel carries one forced reversal strip. The $5$ counts the curvature components carried by that strip; $\pi^2/d$ is the per-route curvature share; $4\pi/3$ is the isotropic scalar readout. The muon is therefore the electron baseline plus one projected node burden.
Mass ratio
$\dfrac{m_\mu}{m_e} = 1 + \dfrac{20\pi^3}{3} = 207.71$
207.71  vs  206.77 exp  (+0.45%)
Tree-level · zero fitted parameters
Tau  ·  n = 3  ·  Two reversal strips  ·  Koide closure  SC
Corner saturation [SC]
At $n=3$, both tangential channels carry one reversal strip each: $(f_1, f_2) = (c, c)$. The normalised frustration norm $\|\mathbf{f}\|^2 = c^2$ is maximal — no further eigenmode can fit.
Amplitude-space invariant [SC]
$Q_A = \tfrac{1}{3}(1 + \|\mathbf{f}\|^2/c^2) = \tfrac{1}{3}(1+1) = \dfrac{2}{3}$
Koide invariant
$Q \equiv \dfrac{m_e+m_\mu+m_\tau}{\left(\sqrt{m_e}+\sqrt{m_\mu}+\sqrt{m_\tau}\right)^2} = \dfrac{2}{3}$
How the tau ratio is fixed: the tau is the two-strip state, but BCT does not obtain it by adding an arbitrary second strip. At $n=3$ both tangential closure channels are simultaneously saturated, so the ratio is fixed by the saturation invariant $Q = 2/3$, not by a free strip-cost parameter. With $m_e$ and the muon ratio already fixed, this constraint determines the tau ratio.
Tau ratio (from muon + Koide)
$m_\tau/m_\mu = 16.81$
16.81  vs  16.82 exp  (−0.03%)
Tree-level (Koide route) · $n_{\text{max}} = 3$ · fourth generation [NG] inadmissible
Generation Count  SC  NG
nmax = 3
Three generations derived
Fourth generation [NG] inadmissible

§ — Boundary Geometry Predictions
Nucleon Masses and Proton Radius
Proton and neutron masses are derived from boundary geometry without fitting to nuclear data. The neutron–proton mass difference — which determines the stability window for nuclear matter — emerges as a structural consequence, not a parameter.
Dualcore derivation spine  SC
Dualcore means two winding centres bound by a seam: the nucleon topology. It is not a collection of detachable sub-particles, but a single boundary self-contact structure. The seam class fixes the route inventory: exposed dualcore $(4,2)$ gives $N_p = 20$; hidden dualcore $(3,3)$ gives $N_n = 18$.
$(4,2) \rightarrow N_p = 4^2 + 2^2 = 20, \qquad (3,3) \rightarrow N_n = 3^2 + 3^2 = 18$
The same isotropic projector used in the muon derivation reads the dualcore curvature into a scalar mass. What changes is the trace supplied by the seam. The small $O(\alpha)$ bracket then splits the shared tree-level dualcore baseline into proton and neutron readouts.
Projection firewall  PL  NG
Quark language is bookkeeping for internal dualcore routing. It does not add smaller detachable particles. The dualcore is one indivisible boundary structure: its internal routes cannot be detached without violating the healing-length floor. Fractional charges are routing coordinates, not free sub-particles.
Proton Mass Ratio  SC
mp me = 1600π³ 27 [ 1 − α 2 ( π 10 1 8 ) ]
= 1836.141  (−0.0006%)
Tree-level baseline $M^*/m_e = 1600\pi^3/27 \approx 1837.4$ · corrected by $O(\alpha)$ seam term
Experiment: 1836.153
Neutron Mass Ratio  SC
mn me = 1600π³ 27 [ 1 + α 2 ( π 10 1 8 ) ]
= 1838.678  (−0.0003%)
Shared tree-level baseline $M^* = 1600\pi^3/27$ · corrected by $O(\alpha)$ frustration term
Experiment: 1838.684
n–p Mass Splitting  SC
Δm = α · 1600π³ 27 ( π 10 1 8 )
= 1.296 MeV  (+0.21%)
Experiment: 1.293 MeV
Proton Charge Radius  SC
Rp = 0.841 fm
Experiment: 0.8409 fm
+0.04%

§ — Tangential-Closure Tiling
Atomic Shell Structure
Around a dualcore nuclear anchor, monocore electrons tile the tangential surface as admissible closure configurations. Shell capacities, period doubling, and chemical family structure follow from $d_T = 2$ and CAP — no quantum numbers are imposed.
Shell capacities  SC
$C_n = 2n^2$
Route factorisation over $d_T = 2$ tangential dimensions gives $n^2$ orbital cells per shell. CAP provides two orientations per cell.
$n=1{:}\;2$  ·  $n=2{:}\;8$  ·  $n=3{:}\;18$  ·  $n=4{:}\;32$
Period doubling  SC
Periods: $2,\; 8,\; 8,\; 18,\; 18,\; 32,\; 32,\; \ldots$
Each shell capacity appears twice in the periodic table. Both CAP orientations must complete per envelope before impedance ordering advances to the next shell.
Noble gas cumulative counts  SC
$2,\; 10,\; 18,\; 36,\; 54,\; 86,\; 118$
Closed-shell configurations match the noble gases. Chemical family structure follows from the tiling geometry — not from an imposed aufbau rule.

§ — Structural Interlocks
Cross-Domain Interlocks
The results above are not independent. Each interlock is a single structural input that fixes two results simultaneously — in different domains, with no additional freedom.
Projector universality  SC
$P[Q] = \dfrac{4\pi}{3}\,\mathrm{tr}\,Q$
Same projector in muon and proton. Only the trace changes — the projector carries no freedom between sectors.
Muon: $\mathrm{tr} = 5\pi^2/d$  ·  Proton: $\mathrm{tr} = N_p^2\pi^2/d^2$
Per-route normalisation  SC
$|a_0|^2 = \dfrac{\pi^2}{d}$
Locked by the same three [SC] inputs in both lepton and dualcore sectors: curvature quantum $\pi$, quadratic functional, isotropic share $1/d$.
Locks muon node cost, proton baseline, and $m_p/m_\mu = 80/9$ simultaneously
Casimir function — two levels  SC
$\dfrac{1}{2\,C_F(SU(d))}\bigg|_{d=2} = \dfrac{2}{3} \qquad \bigg|_{d=3} = \dfrac{3}{8}$
Same formula at two levels: $d=2$ gives Koide $Q=2/3$; $d=3$ gives electron baseline exponent $3/8$. Any $\kappa\neq 1$ breaks the $d=2$ check.
$1/d$ ratio — three appearances  SC
$\text{projector}\;\tfrac{4\pi}{3},\quad f'(0) = -\tfrac{1}{3},\quad \text{impedance share}\;\tfrac{1}{d}$
Three structurally independent appearances of the same architectural ratio, all forced by $(d_T,d_V)=(2,1)$. Not reparameterisations of each other.
Gauge-completion interlock  SC  PL
$U(1)_{\mathrm{wind}} \times SU(2)_{T\text{-routing}} \times SU(3)_{\mathrm{seam}} \Rightarrow SU(3)\times SU(2)\times U(1)$
The gauge product is not inserted as a separate symmetry assumption. $U(1)$ comes from integer tangential winding, $SU(2)$ from the two-channel complex tangential routing doublet, and $SU(3)$ from the three-packet dualcore seam. The same $N_c=3$ seam count also supports confinement and the anomaly-balance colour factor, so the sectors cross-lock rather than float independently.
Origins: winding phase  ·  tangential doublet  ·  seam triplet  ·  Casimir reciprocity $C_F(SU(2))C_F(SU(3)) = 1$
Firewall: gauge-group language is projection bookkeeping; the underlying structural claim is routing geometry, not gauge-field ontology.
Proton/muon ratio — derived cross-check  SC
$\dfrac{m_p}{m_\mu} = \dfrac{N_p^2}{5d^2} = \dfrac{400}{45} = \dfrac{80}{9} \approx 8.889$
Not an independent prediction — the ratio of two projector outputs, each already locked. Agreement with experiment (+0.10%) confirms mutual consistency of the projector normalisation and route count across sectors.
$80/9 = 8.889$ (BCT)  vs  $8.880$ (exp)  ·  +0.10%

§ — Periodic Table Predictions
Covalent Radii — 84 Elements vs NIST
The V1 model applies the BCT boundary geometry to atomic structure with zero free parameters. Predicted covalent radii are compared against NIST experimental values across 84 elements spanning the periodic table.
84
Elements Tested
7.0%
RMSE vs NIST
±15%
All Elements Within
0
Free Parameters
V1 covalent radius prediction errors across 84 elements
The V1 model is the simplest zero-parameter implementation of the BCT boundary geometry applied to atomic radii. The 7.0% RMSE represents the baseline accuracy before multi-loop corrections (V2, in preparation). All 84 elements fall within ±15% of experimental values — a result achievable with zero fitting degrees of freedom.

§ — Geometric Impedance Eigenvalue
The Fine-Structure Constant
α is derived as a geometric impedance eigenvalue of the monocore coupling cycle. It is not a fitted parameter; the formula follows structurally from the 2T+1V boundary geometry. The tree-level result is exact by construction; the realised value incorporates the interaction-enhanced dimensional reduction (IEDR) correction.
P2-SC-ALPHA · [SC] — Tree-Level
α−1 = 4π3 + π2 + π
= 137.036 006…
The three additive terms correspond to the three primitive structural contributions of the 2T+1V boundary: the volumetric coupling (4π³), the surface term (π²), and the boundary-line correction (π). Each term is geometrically sourced; no dimensional constants enter.
Convergence to CODATA 2022 — α⁻¹
Tree-level
137.036 006
Realised (IEDR)
137.035 999 216
CODATA 2022
137.035 999 177
Window: 137.035 990 — 137.036 010  ·  Realised vs CODATA: +0.29 ppb
BCT Tree-Level  SC
α⁻¹ = 137.036 006…
= 4π³ + π² + π  ·  exact by construction
BCT Realised (IEDR)  SC
α⁻¹ = 137.035 999 216
Four geometric steps shift the tree-level result to the realised value:
Step 1 — Throat slope [SC]
Each of d = 3 boundary DOFs contributes ±1/d to the circumference slope (frustrated tangential: −1/d, smooth volumetric: +1/d). Result: f′(0) = (dV − dT)/d = (1 − 2)/3 = −1/3.
Step 2 — Integrated termination curvature [SC]
Gauss–Bonnet on the annulus converts throat slope to integrated curvature: IT = 2π(f′(0) − 1) = −8π/3. Outer curvature: IO = 4π − IT = 20π/3.
Step 3 — IEDR (impedance-extensivity relation) [SC]
Independent closure factors compose multiplicatively → Cauchy extensivity forces β = 1. Impedance elasticity ηZ = xZ′(x)/Z(x) = 2.882 at x = π. Angular patch count N = Z(π)ηZ = 1,440,898.
Step 4 — Realisation shift [SC]
Fractional shift δx/x = IO/(6π · ZηZ) = (3 − f′(0))/(3 · ZηZ). IEDR angular projection maps πeff > π through the S² averaging factor; the measurement-scale scalar lies below π by ~0.77 ppm, giving α⁻¹ = 137.035 999 216.
vs CODATA: +0.29 ppb
CODATA 2022  EI
α⁻¹ = 137.035 999 177
Combined relative uncertainty: 1.5 × 10⁻¹⁰

§§2–10 — Projection Recoveries
What Paper 2 Recovers
Every entry below is derived from the 2T+1V boundary architecture. No new ontological primitives are introduced. Quantitative results shown in earlier cards are not repeated here.
01
Boundary Vortex Uniqueness — the monocore is the unique single-channel topology that localises curvature admissibly. Pure T-mode and pure V-mode both fail; only the coupled T–V vortex survives. SC
02
Mass as Stored Curvature — $m \propto C_\text{total}$. Mass is not a property assigned by fiat; it is the curvature inventory of an extended boundary structure. SC
03
Inertia as Redistribution Cost — the cost of reorganising stored curvature under the impedance law. No separate law of inertia. SC
04
Point-Particle Exclusion — $\Theta(x) \geq \ell_m > 0$ at all core points. Zero-radius cores are inadmissible on two independent grounds; UV divergences do not arise. NG
05
Equivalence Principle — Source Identity — inertial and gravitational mass project from the same $C_\text{total}$. There is no second mass concept. SC
06
Spin-½ from CAP — core admissibility parity is a binary invariant forced by $d_V = 1$; the CAP doublet reads as the fundamental representation of $SU(2)$: $R(2\pi) = -\mathbf{I}$. SC
07
Fermionic Exchange Phase — exchanging two identical monocores with opposite CAP produces $e^{i\pi} = -1$; the phase is locked by $\Delta\phi_\text{CAP} = \pi$, not a free braid parameter. PL
08
Pauli Exclusion Principle — geometric consequence of finite coherence thickness on a 2D routing surface; at most two electrons per route cell (distinguished by CAP). SC
09
Born Rule — $f_i = |\langle \phi_i, \psi \rangle|^2$ from realization-measure counting. $U(1)$ phase invariance forces $\mu = |\psi|^2$; no probability postulate required. PL
10
Heisenberg Uncertainty — $\Delta x\,\Delta p \geq \hbar/2$ as admissibility width; complementary variables are Fourier-dual constraint types. Not fundamental indeterminacy. PL
11
Schrödinger Equation — $i\hbar\,\partial_t\psi = [-\hbar^2\nabla^2/2m + Z_B]\psi$; the unique first-order, linear, norm-preserving evolution in the Hilbert-space coordinate. Factor $i$ forced by skew-adjointness. PL
12
Wavefunction Collapse Is Not Ontic — measurement is boundary coupling that imposes additional admissibility constraints ($\mathcal{A} \to \mathcal{A}' \subset \mathcal{A}$). No observer privilege. NG
13
Canonical Commutator — $[\hat{x},\,\hat{p}] = i\hbar$ follows from operator definitions; non-commutativity reflects finite coherence resolution, not a primitive quantum postulate. PL
14
Apparent Quantum Randomness — outcomes appear random because the post-measurement constraint underdetermines the realisation within each admissibility class. The boundary is deterministic. SC
15
$SU(3) \times SU(2) \times U(1)$ Gauge Product — all three factors forced: $U(1)$ from winding, $SU(2)$ from complexified $d_T = 2$, $SU(3)$ from dualcore seam in $\mathbb{C}^3$. SC
16
Confinement — free quarks are structurally inadmissible; the dualcore seam cannot open without violating the healing-length floor. NG
17
Neutrino Classification — propagating event-form of non-storable V–T mismatch. Not curvature-storing matter, not radiation, not a fourth matter class. SC
18
Lepton Universality — three eigenmodes share the same external topology; reversal strips are internal to the core. Universality is structural identity, not a postulated symmetry. SC