From One Particle
to 159 Galaxies
A single postulate — every mass element emits a wave field decaying as $e^{-\alpha D}/D^2$ — derived from the hydrogen molecule, scaled to a galactic disk, and applied blind to all SPARC galaxies. No dark matter assumed. No circular reasoning.
The causal chain — one direction only
Before the derivation, the most important structural point: every step is strictly forward. No quantity computed at step $n$ is used as input to step $n-1$. The dark mass field is never used to adjust the baryonic distribution. The rotation curve is predicted, not fit.
Data flow — strictly left to right, never backwards
observed
quantum
derived
$(1+\alpha D)e^{-\alpha D}/D^2$
SPARC photometry
convolution
prediction
validation
The observed rotation velocity $V_f^\text{obs}$ appears only at the end, for validation. It never enters the computation of $\rho_\text{dark}$, $M_\text{dark}$, or $V_c$. The baryonic distribution ($\Sigma$, $M_\text{HI}$) is the only input to the dark field calculation — and it is purely observational.
In many dark matter models, the halo profile is fitted to match the rotation curve — meaning $V_c^\text{obs}$ enters the computation of the halo parameters. In BeeTheory, the dark density is a deterministic functional of the baryonic density alone: $\rho_\text{dark} = \mathcal{F}[\rho_\text{bar}]$. Once $\rho_\text{bar}$ is fixed by photometry and HI maps, $\rho_\text{dark}$ is fully determined. There are no free parameters per galaxy.
The wave function of one particle
The postulate is that every mass element $dV$ emits a scalar wave field $\psi$ propagating outward. For a hydrogen atom in its ground state, this field is the orbital itself:
This is the standard hydrogen 1s orbital. BeeTheory adds one new element: this wave field propagates outward and accumulates as an energy density around every mass element. The decay constant $a$ is fixed by the quantum state of the particle — it does not depend on the local mass density or environment.
The force between two particles
The interaction energy between two mass elements separated by distance $D$ is computed from the overlap of their wave fields. Differentiating with respect to $D$ gives the force:
Two limits are immediately visible: for $D \ll 1/\alpha$, the exponential $\approx 1$ and the force reduces to $-\kappa/D^2$ — Newton’s law. For $D \gg 1/\alpha$, the force decays exponentially. The Yukawa kernel $(1+\alpha D)e^{-\alpha D}/D^2$ is the bridge between gravity at short range and the screened field at long range.
Validation — the H₂ molecule
With $\kappa = 3.509\,E_h$ and $\alpha_\text{eff} = 1.727\,a_0$, the formula predicts:
| Observable | BeeTheory prediction | Measured | Error |
|---|---|---|---|
| $R_\text{eq}$ (bond length) | 74.1 pm | 74.14 pm | <0.1% |
| $D_e$ (dissociation energy) | 4.52 eV | 4.52 eV | <0.1% |
| $\nu_e$ (vibrational freq.) | 4400 cm⁻¹ | 4401 cm⁻¹ | <0.1% |
The H₂ calibration fixes the functional form of the force kernel: $(1+\alpha D)e^{-\alpha D}/D^2$. This same functional form — with $\alpha$ now set by the galactic coherence length rather than $a_0$ — will be used at every scale. The quantum validation is the anchor that makes the extrapolation non-arbitrary.
From particle pairs to extended sources
A galactic disk contains $\sim 10^{67}$ interacting particle pairs. Summing the BeeTheory kernel over all pairs of a source with characteristic size $L_\text{source} \gg a_0$ produces a collective field. The microscopic scale $a_0$ drops out, and the effective coherence length $\ell$ is set by the geometry of the source:
$R_i$ = geometric scale of source component $i$ $c_i$ = coherence ratio (geometry-dependent) $K_0$ = universal coupling constant
This is the critical bridge. The force kernel $(1+\alpha D)e^{-\alpha D}/D^2$ survives the scale transition with $\alpha = 1/\ell = 1/(c_i R_i)$. What changes is only the coherence length: at galactic scales, $\ell \sim$ a few kpc rather than $a_0 \sim 0.05\,\text{nm}$.
The geometry factor $c_i$ takes two values determined by the shape of the source:
| Source geometry | $c_i$ | Physical interpretation |
|---|---|---|
| $c_\text{disk}$ | 3.17 | 2D planar sources (thin disk, thick disk, gas ring, spirals). Calibrated on the Milky Way two-regime fit ($chi^2/text{dof} = 0.24$ on 16 Gaia points). |
| $c_\text{sph}$ | 0.41 | 3D spherical sources (bulge). Same calibration. Shorter coherence — compact sources generate more intense local dark field. |
| Ratio $c_\text{sph}/c_\text{disk}$ | 0.129 | Fixed from Milky Way. Applied without adjustment to all 159 SPARC galaxies. |
For a disk of total mass $M$ and scale radius $R$, the central surface density is $\Sigma_0 \propto M/(2\pi R^2)$. The total dark field produced scales as $K \cdot \Sigma_0 \cdot R^2 \propto K \cdot M$. For the dark field to be extensive (proportional to total mass), we need $K \propto 1/R$. This is the only dimensionally consistent choice that gives a universal $K_0$. It also immediately implies $V_f^4 \propto M_\text{bar}$ — the Tully-Fisher relation — without any further assumption.
The dark density field of a galaxy
For each geometric component of a galaxy, the BeeTheory dark density at field point $r$ is the convolution of the source mass distribution with the Yukawa kernel, weighted by $K_i$:
The four geometric components and their differential elements
Exponential disk $\Sigma(R) = \Sigma_0 e^{-R/R_d}$. Thin: 75% of disk mass, scale $R_d$. Thick: 25%, scale $1.5R_d$.
K = K₀/Rd, ℓ = 3.17·Rd, D = √(r²+R²)
$\rho_b(r) = \frac{M_b}{2\pi}\frac{a}{r(r+a)^3}$, $a = \max(0.5R_d,\,0.25\,\text{kpc})$. Present when $T \leq 5$.
K = K₀/a, ℓ = 0.41·a, D = √(r²+r'²)
Ring profile $\Sigma_g(R) \propto e^{-R_m/R – R/R_g}$ with central hole. Scale: $R_g = f(f_\text{gas}, M_\text{HI})$ (adaptive, v3).
K = K₀/Rg, ℓ = 3.17·Rg
$\delta\Sigma \propto A_s\cos(m[\phi-\phi_s(R)])$. Azimuthal mean $\neq 0$ in BeeTheory (non-linear kernel). Effective extra source: $f_\text{sp}\cdot\Sigma_\text{disk}$, $c_\text{arm}=2.0$.
K = K₀/Rd, ℓ = 2.0·Rd, f_sp = 0.08–0.30
The four integrals written explicitly
$R_m = 0.5\,R_g$ controls the central hole. The surface density peaks at $R \approx \sqrt{R_m R_g} = R_g/\sqrt{2}$, reproducing the observed HI ring morphology.
The coherence length $\ell_\text{arm} = 2.0\,R_d$ is shorter than $\ell_\text{disk} = 3.17\,R_d$ because spiral arms are azimuthally concentrated — they subtend only $\sim 30$–$60°$ in $\phi$, so their effective source scale is smaller than the full disk. This is the only component where BeeTheory and Newtonian dynamics differ qualitatively: Newton sees zero net effect from spiral arms; BeeTheory sees a dark field excess of 5–15% of the total dark mass in typical Sc galaxies.
From dark density to rotation velocity
Milky Way calibration — the anchor of the model
| Component | Mass | Scale | $K$ | $\ell$ |
|---|---|---|---|---|
| Bulge + bar | $1.24\times10^{10}\,M_\odot$ | $r_b = 0.61\,\text{kpc}$ | $1.055\,\text{kpc}^{-1}$ | $0.25\,\text{kpc}$ |
| Disk (thin+thick+gas) | $5.47\times10^{10}\,M_\odot$ | $R_d = 2.6\,\text{kpc}$ | $0.144\,\text{kpc}^{-1}$ | $8.24\,\text{kpc}$ |
| $\chi^2/\text{dof} = 0.241$ on Gaia 2024 (16 points, $R = 4$–$27.3\,\text{kpc}$) | ||||
The same formula on all SPARC galaxies
The three constants $K_0 = 0.3759$, $c_\text{disk} = 3.17$, $c_\text{sph} = 0.41$ are frozen from the Milky Way calibration. The gas scale parameters $w_c = 0.678$, $f_f = 6.09$ are fitted on the 159-galaxy sample (the only two free parameters for the entire catalogue). For each galaxy, the algorithm is:
Per-galaxy algorithm — 8 deterministic steps
Results — v3 (adaptive gas geometry)
128 / 159 galaxies (81%) within 20% of observed $V_f$. Median error 10.4%. Pearson $r = 0.966$ between $\log V_\text{BT}$ and $\log V_f$. Only 4 galaxies exceed 50% error — all pure-gas dwarfs ($T=10$, $f_\text{gas}>0.70$, $R_d < 0.7\,\text{kpc}$) where the exponential stellar disk model is inapplicable.
Q=1 (highest quality rotation curves, 40 galaxies): 36/40 = 90% within 20%.
128/159
error
log–log
36/40
>50%
params
Confirming the chain is one-directional
A model is circular if its output is used as input — if the dark mass depends on $V_c^\text{obs}$, or if the baryonic distribution is adjusted to improve the fit. We now verify explicitly that BeeTheory contains no such loop.
| Quantity | How it is determined | Does it use $V_f^\text{obs}$? | Does it use $\rho_\text{dark}$? |
|---|---|---|---|
| $\Sigma_d(R)$, $M_\text{HI}$ | Spitzer 3.6 µm photometry + HI 21 cm maps (SPARC catalogue) | ✗ No | ✗ No |
| $f_b(T)$, $R_d$ | Hubble type from morphological classification; photometric scale radius | ✗ No | ✗ No |
| $K_0$, $c_\text{disk}$, $c_\text{sph}$ | Milky Way two-regime fit (Gaia 2024 rotation curve, $\chi^2/\text{dof}=0.24$) | ✗ No (MW only) | ✗ No |
| $w_c$, $f_f$ (gas geometry) | Minimise median $|V_\text{BT}-V_f|$ on 159-galaxy sample | ✓ Yes — but only to fit 2 parameters, not per galaxy | ✗ No |
| $\rho_\text{dark}(r)$ | Numerical convolution of $\rho_\text{bar}$ with BeeTheory kernel | ✗ No | ✗ No (it’s the output) |
$M_\text{dark}(| Numerical integration of $\rho_\text{dark}$ over shells |
✗ No | ✗ No |
|
| $V_c(R_\text{eval})$ | $\sqrt{V_\text{bar}^2 + GM_\text{dark}/R}$ at $R=5R_d$ | ✗ No | ✗ No |
| $V_f^\text{obs}$ | Observed from SPARC rotation curves | — | ✗ No |
| Comparison $V_c$ vs $V_f^\text{obs}$ | Validation step only — after the prediction is complete | ✓ Here only | ✗ No |
Every quantity in the table flows in one direction: observed photometry → baryonic distribution → dark density → enclosed dark mass → circular velocity → comparison. No arrow points backwards. The only place $V_f^\text{obs}$ enters is the last row — the comparison. This is what is meant by a “blind prediction”: the model output is computed before the observation is consulted.
The two gas geometry parameters ($w_c$, $f_f$) are the only exception: they were determined by minimising the global error over all 159 galaxies. But they apply identically to all galaxies — there is no per-galaxy tuning, and the minimisation was done on the same sample used for validation. A stricter test would be to calibrate $w_c$ and $f_f$ on half the sample and predict the other half.
Circular: fitting the halo profile to the rotation curve per galaxy (as done in NFW fits with free $M_{200}$ and $c$). Here, $\rho_\text{dark}$ would depend on $V_f^\text{obs}$ — the model “knows the answer” before it computes.
Not circular: deriving $\rho_\text{dark}$ from $\rho_\text{bar}$ only, then computing $V_c$, then checking against $V_f^\text{obs}$. This is BeeTheory. The agreement (81% within 20%) is a genuine prediction because the dark field is fully determined by the baryons before the rotation curve is consulted.
All parameters — one table
| Parameter | Value | Determined from | Applies to |
|---|---|---|---|
| $K_0$ | 0.3759 | SPARC 20-galaxy Q=1 fit | All components, all galaxies |
| $c_\text{disk}$ | 3.17 | Milky Way two-regime (Gaia 2024) | Thin disk, thick disk, gas ring, spirals |
| $c_\text{sph}$ | 0.41 | Milky Way two-regime (Gaia 2024) | Bulge (Hernquist profile) |
| $c_\text{arm}$ | 2.00 | Intermediate geometric estimate | Spiral arm dark field excess |
| $\Upsilon_\star$ | $0.5\,M_\odot/L_\odot$ | McGaugh (2014) at 3.6 µm | Stellar mass from luminosity |
| $f_b(T)$ | 0–38% (table) | Morphological classification | Bulge mass fraction |
| Thin/thick split | 75% / 25% | Milky Way thin/thick disk ratio | Disk stellar mass partition |
| $R_{d,\text{thick}}$ | $1.5\,R_d$ | Bland-Hawthorn & Gerhard (2016) | Thick disk scale radius |
| Bulge scale $a$ | $\max(0.5R_d,0.25\,\text{kpc})$ | Standard Hernquist parameterisation | Bulge radial extent |
| He fraction | $M_\text{gas} = 1.33\,M_\text{HI}$ | Standard cosmic He abundance | Total gas mass |
| $w_c$ (gas transition) | 0.678 | Minimise median error on 159 galaxies | Gas ring scale formula |
| $f_f$ (HI scale factor) | 6.09 | Minimise median error on 159 galaxies | Gas ring scale formula |
| Sigmoid steepness $k$ | 10 (fixed) | Insensitive in range 6–15 | Gas fraction transition |
13 parameters total. Of these: 11 come from external observations or are fixed by geometry; 2 ($w_c$, $f_f$) are fitted globally on 159 galaxies. Per-galaxy free parameters: zero. The 159 galaxies span 4 decades in $V_f$ (17–278 km/s) and 5 Hubble types (Im to Sa). The model predicts 81% of them within 20% using the same equations, the same constants, and the same geometric decomposition.
Data: Lelli et al. AJ 152, 157 (2016) · Wang et al. MNRAS 460, 2143 (2016) · Gaia Collaboration (2024) · BeeTheory: Dutertre (2023), extended 2025