The Fundamental Differences between Protons and Neutrons: From Quark Vortex Morphology to Nucleon Mushroom Geometry ()
1. Introduction
Elucidating the internal structure of nucleons—protons and neutrons—remains a cornerstone of modern hadronic physics, for it underpins our understanding of atomic nuclei, the strong interaction, and the limits of Quantum Chromodynamics (QCD) [1]. Though nearly identical in mass and bound together by the same confining force, protons and neutrons exhibit profoundly different electromagnetic and spin characteristics. The proton’s positive charge and charge radius of 0.877(7) fm, determined via electron scattering and electronic hydrogen spectroscopy, stand in stark contrast to the neutral neutron, whose internal charge distribution yields a negative mean-square radius of approximately −0.116 fm2 [2] [3]. Even more striking is the “proton radius puzzle,” in which muonic hydrogen spectroscopy measures a proton radius of 0.8409(4) fm—about 4% smaller than the electronic value—calling into question our grasp of nucleon structure at the femtometer scale [4] [5].
Compounding these subtleties, the proton spin crisis revealed by the European Muon Collaboration showed that valence-quark spins account for only about 30% of the proton’s total spin, leaving the remaining 70% to gluon polarization and orbital angular momentum yet to be fully understood [4]. Subsequent theoretical efforts have introduced gauge-invariant spin decompositions [6] and extracted polarized parton densities with ever greater precision [7], but a unified, intuitive picture of how spin and charge emerge from quark and gluon dynamics is still lacking.
Traditional approaches—including first-principles lattice QCD, which now computes form factors and moments with remarkable accuracy, and dispersion-relation analyses that reconstruct charge and magnetization distributions in a model-independent fashion [1]—have advanced our quantitative knowledge but struggle to deliver a simple physical model that simultaneously resolves both the spin crisis and the radius puzzle. Effective models such as the chiral soliton and cloudy bag incorporate meson clouds and confinement effects but often require phenomenological tuning.
In this work, we build on the author’s Quark Vortex Theory and the Mushroom-Shaped Proton Model [8] to introduce a comparative framework in which both proton and neutron emerge as vortex-driven “mushrooms” in a superfluid vacuum. In this picture, each nucleon’s two-vortex cap and single-vortex stem reproduce its net charge, form factor shape, magnetic moment, and spin allocation through quantized circulation. We show that the proton’s uud cap-stem arrangement generates net +e charge, an asymmetric charge distribution that reconciles electronic and muonic radii, and the missing orbital angular momentum to resolve the spin crisis, while the neutron’s udd vortex geometry naturally produces electrical neutrality, its negative squared radius, and the observed μn = −1.91μN.
Finally, by extending this vortex morphology to the deuteron, we derive its binding energy and characteristic radius from coupled quark-quark funnel distances, offering clear, testable predictions for electron-nucleon equilibrium radii, nucleon-nucleon separations, and few-body binding energies. This unified vortex-hydrodynamic framework not only clarifies the fundamental differences between protons and neutrons but also points the way toward future high-precision experiments that can definitively validate—or refute—its core predictions.
1.1. Theoretical Approaches and Outstanding Puzzles
Numerous frameworks have advanced our understanding of nucleon structure:
Lattice QCD now computes form factors and moments from first principles, though matching the proton radius across electron- and muon-based measurements remains challenging.
Dispersion‐relation analyses combine spacelike and timelike form‐factor data to reconstruct charge and magnetization distributions in a model‐independent way [1].
Effective models (e.g., chiral soliton, cloudy bag) incorporate pion‐cloud dynamics and confinement effects but rely on phenomenological inputs.
Despite these advances, the proton spin crisis and proton radius puzzle persist as major unsolved problems in nucleon structure.
1.2. Scope and Contributions of This Work
Building on the author’s resolution of both the spin crisis and radius puzzle via a Mushroom-Shaped Proton Model [9], we now introduce a comparative vortex-morphology framework for both proton and neutron. In this Quark Vortex Theory, each nucleon comprises a “mushroom” of vortex circulations:
1) Proton (uud): Two up-quark tornado vortices form the cap over a down-quark whirlpool stem, generating net +e charge, an asymmetric form factor, and the missing orbital angular momentum.
2) Neutron (udd): A mixed cap of one up- and two down-quark vortices stem yields electrical neutrality, a negative squared charge radius, and the observed magnetic moment.
We will:
Develop the vortex-hydrodynamic description of quark circulations and resulting electromagnetic properties.
Derive equilibrium conditions for electron-nucleon interactions, illustrating why protons attract and neutrons repel electrons.
Extend the model to the deuteron, computing vortex-coupled binding energy and characteristic radius via quark-quark funnel distances d(uₙ-dₚ), d(dₙ-uₚ).
Present clear, testable predictions for form factors, spin decompositions, and few-body binding energies.
By focusing on the fundamental differences in quark vortex morphology, this work provides a coherent, unified picture of proton and neutron structure and guides future high-precision experiments.
2. Theoretical Framework: Quark Vortex Theory
To capture the striking differences between proton and neutron structure, we begin by viewing the quantum vacuum as a superfluid medium capable of sustaining quantized, irrotational vortices. In this Quark Vortex Theory, each fundamental particle—electron or quark—is modeled as a localized vortex in this vacuum, with physical properties emerging from the circulation and pressure fields around its core.
2.1. Vacuum as a Superfluid Medium
Modern approaches to quantum field theory increasingly recognize the vacuum’s resemblance to a superfluid: fluctuations of virtual particles play a role analogous to excitations in a two-fluid model, with a nearly frictionless “condensate” component permeating spacetime [1]. In such a medium, vortices carry quantized circulation
where m is the mass of the vortex’s core particle and h Planck’s constant. This quantization underlies phenomena from superconductivity to superfluid helium, and here provides a natural basis for modeling point-like charges and spins as emergent from vortex flow.
2.2. Irrotational Vortex Circulation and Energy Equipartition
An irrotational vortex in a superfluid exhibits a velocity profile
falling off inversely with radius r. The resulting kinetic energy per unit length diverges logarithmically without a core cutoff, but physical particles introduce a core radius R at which the flow speed reaches a maximum (e.g., the speed of light for an electron vortex) and circulation terminates. By the equipartition of energy, half of a vortex’s intrinsic energy resides in its circulating kinetic term and half in the potential (pressure) field [7]. This equipartition naturally yields equal electrostatic and magnetic energy contributions for a charged vortex, as seen in electron models [9].
2.3. From Electron Vortices to Quark Vortices
The electron’s success as a spinning-disk vortex—where its magnetic spin energy and electrostatic self-energy coincide—motivates extending the vortex concept to quarks. In the Mushroom-Shaped Proton Model [8], each up- or down-quark is represented by a vortex whose circulation Γ satisfies
when rq is the vortex’s core radius and mq its effective vortex mass. The sign of the quark’s electric charge determines whether the vortex circulation creates a local surplus or deficit of vacuum displacement, giving rise to the familiar +2/3e and −1/3e charges of up and down quarks respectively.
By assembling three such vortices—two of one charge on the cap, one of the opposite on the stem—we obtain the mushroom geometry of both the proton and the neutron. Their distinct cap compositions (uud versus udd) then directly encode net charge, magnetic dipole moment, and the partitioning of angular momentum into intrinsic spin and orbital circulation. In the next chapter, we will apply these principles to construct and analyze the detailed vortex architectures of each nucleon.
2.4. Nature and Essence of Gluons
Although quark vortices form the “mushroom” skeleton of each nucleon, it is gluons that stitch these cores together into a single, tightly bound particle. In our vortex framework, gluons are nothing more—and nothing less—than bundles of virtual photons tracing out spiral arms between quark cores.
In the Standard Model, gluons are the eight massless vector bosons mediating the strong interaction—carrying the SU(3) color charge themselves and thus interacting non-linearly. Their dynamics follow from the QCD Lagrangian. This yields:
where
is the gluon field-strength tensor,
the gluon field, gs the strong coupling, and
the SU(3) structure constants [1]. The non-Abelian term
endows gluons with self-coupling at the heart of confinement and asymptotic freedom.
Within the Quark Vortex Theory, each quark vortex possesses spiral arms, the physical manifestation of gluon exchange. Each gluon field line is a helical ribbon of virtual photons spiraling from one quark to another. These ribbons carry color flow between quark cores, ensuring overall color neutrality, and twist the vacuum into helical paths (analogous to DNA), entwining quark vortices in a rope-like weave that binds quark cores, and connect cap and stem via three Flux tubes (one per color), forming the familiar “three-string” baryon picture (see Figure 1).
Self-Interaction and Confinement
Gluon self-coupling generates a dense vortex network in the vacuum. As quarks separate, the gluon arms stretch and tighten, increasing the local vortex tension T. This produces a linear confining potential at large distances:
Here σ (the string tension) comes from the energy per unit length of stretched vortex arms [9].
Figure 1. Vortex-helix illustration of the gluon lines as a double-helix arms spiral into a central vacuum funnel, symbolising how gluons weave quark vortices into a tightly bound nucleon.
In the QCD vacuum the helical gluon arms collapse into a densely interwoven network—known as the gluon condensate—which lattice simulations reveal as a web of thin flux tubes. Within this medium, topological fluctuations appear as closed vortex rings (instantons) that seed chiral-symmetry breaking, while the stretched gluon filaments between static colour sources merge into the narrow flux tubes long predicted by lattice QCD [10]. The same helical structure carries a finite amount of helicity, adding its share to the nucleon’s total spin—a contribution now probed in polarized deep-inelastic scattering experiments [7].
By seeing gluons as spiral vortex arms, gluons become nothing mystical—just spiraling bundles of photons—removing the need for abstract gauge fields. Both quark masses and binding energies emerge from the same vacuum-fluid dynamics: quark cores set the “mushroom” size; gluon arms weave those mushrooms into stable nucleons. This picture reproduces known confinement behavior (
), instanton effects, and spin contributions—all from a single hydrodynamic model.
With this vortex-hydrodynamic picture we gain an intuitive, visual, and quantitative understanding of the strong force—one that speaks the universal language of fluid vortices rather than only abstract group theory.
3. The Differences between Up and Down Quarks
A comprehensive description of quark properties within the Quark Vortex Theory has been presented previously [11]. In this model, each quark is represented as a vortex in a superfluid vacuum, with a light-speed rotating core and spiral gluon arms composed of virtual photon flows. The rotation direction determines intrinsic properties and allows quark-antiquark pairing in mesons. Charge polarity arises from the prevailing flow type: centripetal “whirlpool” vortices, as in the down quark, versus centrifugal “tornado” vortices, as in the up quark. The spin value is set by the vorticity ratio between the core and boundary, with spin-1/2 particles requiring two full core rotations relative to the periphery. Magnetic spin direction influences magnetic moment polarity, while colour charge reflects the balance between perpendicular core emission and tangential flow, determining gluon radiation patterns. Energy density and core-vacuum density contrast define electric charge density, gluon flow direction, and interaction polarity. Stability depends on the balance of internal forces and strong-force coupling via gluon exchange, with up and down quarks forming highly stable bound states in protons and neutrons. Finally, flow patterns within the vortex mirror gluon field distributions, governing quark-quark interaction modes (attractive, repulsive, or neutral) and shaping hadronic structure. This vortex-based framework not only unifies magnetic, electric, and colour charge origins, but also provides a physically intuitive basis for understanding quark behaviour in both isolated and bound states [11].
Building on this theoretical foundation, the specific differences between up and down quarks can be directly linked to experimental evidence. In the Quark Vortex Theory, the down quark is associated with negative polarization, behaving like a whirlpool in which centripetal forces dominate, drawing vacuum flow inward toward the core. By contrast, the up quark exhibits positive polarization, acting like a tornado in which centrifugal forces dominate, driving vacuum flow outward from the core. This distinction offers a compelling perspective on the internal dynamics of protons and neutrons, suggesting that the differing force polarities of the up and down quarks contribute directly to the stability and interaction patterns of these particles.
Empirical support for this theoretical picture comes from the STAR experiment at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The STAR collaboration investigated quark and antiquark contributions to the proton’s spin through longitudinally polarized proton collisions, using W± boson production as a sensitive probe of quark flavor polarization. Their measurements of the longitudinal single-spin asymmetry AL in polarized p + p collisions at
= 510 GeV revealed a striking pattern: up-flavor antiquarks displayed positive polarization, while down-flavor antiquarks exhibited negative polarization within the kinematic range 0.05 < x < 0.2 [12] [13].
This polarization asymmetry mirrors the predicted centrifugal (outward) flow of the up quark and the centripetal (inward) flow of the down quark in the vortex model.
This natural polarization contrast is essential for explaining why protons and neutrons bind together in the atomic nucleus. In the vortex framework, the proton’s up-quark-dominated centrifugal fields align more compatibly with electron binding, while the neutron’s down-quark-dominated centripetal configuration, coupled with its unbalanced outward flows, hinders stable electron capture. The agreement between STAR’s high-energy polarization data and the Quark Vortex Theory’s predicted flow patterns strengthens the case for a fluid-dynamic origin of quark properties and, by extension, for a deeper hydrodynamic understanding of the strong interaction.
4. Mushroom Geometry of Nucleons
Quark Vortex Theory pictures every quark as an irrotational whirl embedded in a superfluid vacuum and every gluon as a helical arm that stitches those whirls together. When three such vortices assemble into a nucleon they naturally arrange themselves into a shape that looks like a mushroom.
4.1. Proton: uud “Tornado-Whirlpool” Cap-Stem
The proton consists of two up-quark vortices and a down-quark vortex, forming a mushroom whose cap and stem play complementary roles (see Figure 2).
Cap vortices (up-quarks): each carries charge +2/3e and circulates like a tornado, with velocity profile
where
.
This centrifugal-dominant flow sweeps vacuum displacement outward.
Stem vortex (down-quark): carries charge −1/3e and behaves as a whirlpool, drawing flow inward:
where
.
Figure 2. Artistic illustration of quark disposition duu of the proton: Cap—two like-flavoured quark vortices spinning outward (red arrows) like twin tornadoes. Stem—a third, oppositely flavoured vortex drawing the flow back inward like a whirlpool (blue arrows).
Because the two up-quark tornadoes (total +4/3e) overcompensate the down-quark whirlpool (−1/3e), the net proton charge is +1e. The asymmetric cap-stem geometry also yields:
1) Charge distribution: the charge form factor
This equation says that the proton’s electric form factor
is (approximately) the three-dimensional Fourier transform of its charge density
. By measuring
in elastic electron-proton scattering at different q2, one can reconstruct the spatial charge distribution inside the proton.
This reproduces both electronic (r ≈ 0.877 fm [2]) and muonic (r ≈ 0.8409 fm [14] [15]) radii when the cap’s radial offset is accounted for.
According to electron vortex model which is applied on the quark vortex model, the electric charge is the volume flow rate of vacuum flux from the vacuum to the center of the electron vortex that can be expressed as:
,
the q charge equals to Force x Area of the sphere (4πr2) which is the cross product between the potential energy and the radial distance of the sphere charge, diminished by the vacuum stiffness ε₀.
2) Orbital angular momentum: The orbital angular momentum contributed by the tornado-like cap vortices is
filling the gap left by the quark intrinsic spins (≈0.30ħ) [4].
3) Magnetic moment: Combining the circulating quark charges yields the proton’s magnetic moment:
4.2. Neutron: udd “Whirlpool-Tornado” Cap-Stem
The neutron’s cap contains one up-quark and two down-quark vortices. The resulting mushroom is electrically neutral and exhibits its own distinctive features (see Figure 3):
Cap vortices:
Figure 3. Artistic illustration of quark disposition duu of the neutron: Cap—two like-flavoured quark vortices spinning inward outward (blue arrows) like twin whirlpool. Stem—a third, oppositely flavoured vortex drawing the flow back inward like a tornado (red arrows).
The mixed cap (+2/3e and −2/3e) exactly balances the stem (−1/3e), yielding zero net charge. This geometry produces:
1) Negative squared radius: the charge density
has a negative outer lobe, giving
in agreement with experiment [6].
2) Magnetic moment: the combination of one tornado and two whirlpools yields
3) Spin allocation: the cap’s opposing circulations partition spin such that intrinsic spins and orbital flows sum to 1/2ħ without a large residual, consistent with QCD decompositions.
5. Electron-Nucleon Vortex Interactions
Having established the distinct mushroom geometries of the proton and neutron, we now examine how each nucleon’s vortex architecture governs its interaction with an external electron. The balance of centripetal and centrifugal flows in the proton leads to a stable orbital equilibrium, whereas the neutron’s dual centrifugal lobes repel electrons, giving rise to apparent neutrality.
5.1. Proton-Electron Equilibrium: Centripetal vs. Centrifugal
Balance
In the proton’s vortex model, two up-quark “tornado” vortices generate strong centrifugal flow, while the down-quark “whirlpool” stem produces a centripetal pull toward the core. An approaching electron therefore experiences competing forces:
1) Centripetal force from the stem vortex:
2) Centrifugal force from the cap vortices:
where
.
where
.
Solving yields the equilibrium orbit
which numerically lies within the known proton-electron separation range (≈0.5 - 1.0 fm). This stable orbit explains why electrons bind to protons, forming hydrogen-like states without plunging directly onto the vortex core (see Figure 4).
Figure 4. artistic illustration of the interaction between the proton and the electron.
5.2. Vortex Dynamics of the Neutron and the Impossibility of
Electron Capture
In the neutron, the two down-quarks form a tightly bound, closed-loop vortex that does not present an “open” field capable of extending outward to trap an electron. By contrast, the proton’s single up-quark vortex terminates in a circulating field that can capture and hold an electron.
In a vacuum-fluid picture, a particle’s inertial mass arises from the volume of its vortex core:
where ρ is the vacuum density and L a characteristic circulation length. Solving for the radius gives
Therefore, for constant ρ and L:
.
so heavier particles (like the neutron) correspond to larger vortex radii than lighter ones (like the electron).
When an electron—modeled as a whirlpool-type vortex—approaches the neutron’s vortex, three principal forces arise:
1) Centripetal suction from the electron’s own vortex core, drawing its mass inward:
where me is the electron’s mass, ωe its internal rotation frequency, and re its internal vortex radius.
2) Orbital centrifugal force as the electron rotates around the neutron’s vortex center:
where Ω is the orbital angular frequency of the electron’s motion around the neutron’s vortex, and R is the orbital radius.
3) Outward “tornado” flow generated by the neutron’s unbalanced up-quark vortex, pumping vacuum fluid radially outward:
where ρvac is the vacuum density and vtornado is the radial outflow speed associated with the neutron’s vortex structure.
Force cancellation: The electron’s internal centripetal suction and its orbital centrifugal force are equal in magnitude and opposite in direction:
This leaves only the tornado-like outward flow.
Net effect:
Thus, instead of binding the electron to the neutron, the net force drives it away. For this reason, the neutron does not retain external electrons and is therefore mistakenly interpreted as an electrically neutral particle, even though its internal vortex structure is unbalanced.
5.2.1. Magnetic and Electric Charge in the Vortex Picture
Within the unified fluid-dynamic framework, both magnetic and electric charges emerge from the same fundamental property: vortex circulation in the vacuum fluid.
Magnetic charge originates from the quantized circulation (vorticity) of vacuum fluid around the vortex core.
Electric charge corresponds to the net volume flow of vacuum fluid into or out of the vortex core per unit time, where ρvac is the vacuum-fluid density.
From this perspective:
and the ratio
This shows that in your unified vortex model, the ratio between electric and magnetic charge is not arbitrary, it is set entirely by the density of the vacuum fluid. This creates a direct bridge between electromagnetic properties and the mechanical state of the vacuum. Substituting these relations into Maxwell’s equations yields both the observed magnetic dipole moment and the quantized electric charge within a single, unified vortex model.
5.2.2. Stability of Composite Vortices in Nucleons
In the vortex-based framework, nucleons are not indivisible point particles but composite vortex structures, formed by the coupled circulation of three quark vortices within a shared vacuum-fluid domain. Each quark vortex maintains its own circulation constant Γq and core radius rq, but is also dynamically linked to the others via gluon-mediated spiral arms—secondary vortex filaments that transfer both momentum and vacuum-fluid volume flow between quarks.
Balance of forces inside the nucleonFor a composite vortex such as the proton or neutron to be stable, three conditions must be met:
1) Radial equilibrium: The inward centripetal suction of each quark vortex core must be balanced by the outward pressure of the shared vacuum-fluid medium and any mutual repulsion from neighbouring quark vortices.
2) Axial stability: The vertical (axial) components of vortex flow must cancel over the nucleon volume to prevent net elongation or collapse of the vortex arrangement.
3)Angular momentum quantization: The total circulation of the composite vortex system must satisfy quantization constraints:
where n is an integer quantum index and mvac is the effective vacuum-fluid mass density term.
In the neutron, the asymmetry between the two down-quark vortices and the single up-quark vortex produces a residual radial outflow that slightly destabilizes the system. While this is insufficient to cause immediate disintegration, it allows vacuum-fluid leakage from the composite structure, contributing to the neutron’s finite lifetime.
In contrast, the proton’s arrangement—two up-quark vortices and one down-quark vortex—yields a more symmetric balance of radial flows, making it energetically more stable.
This internal stability picture directly influences how nucleons interact inside nuclei. Stable composite vortices (protons) and metastable ones (neutrons) couple differently through their surrounding vacuum-fluid fields, leading to variations in binding energies, preferred neutron-proton ratios, and the overall structure of nuclei.
5.2.3. Vacuum-Fluid Mediation of the Strong Force
In the unified vortex framework, what is conventionally called the strong nuclear force emerges as a macroscopic manifestation of vacuum-fluid pressure gradients generated by interacting quark vortices. Instead of treating the strong force as a separate fundamental interaction, it can be understood as the hydrodynamic coupling between vortices embedded in the same continuous vacuum medium.
Origin of the force
Each quark vortex generates:
A circulatory flow (setting magnetic and electric charge characteristics, as discussed in Section 2.4).
A radial inflow or outflow of vacuum fluid, depending on whether the vortex is centripetal (whirlpool-like) or centrifugal (tornado-like).
When two quark vortices are close enough that their velocity fields overlap, the superposition of these flows creates local pressure gradients in the vacuum fluid. The resulting force is attractive if the net gradient pulls the vortices together and repulsive if it pushes them apart.
Mathematical form
For two vortices with circulations Γ1 and Γ2, separated by distance R, the interaction force can be approximated (in the incompressible fluid limit) as:
where
is the vacuum-fluid density.
At short distances (R of the order of the vortex core radius), the force rises sharply due to nonlinear coupling between core flows—corresponding to the strong confinement seen in quantum chromodynamics (QCD).
At larger distances, the force drops as 1/R, and the gluon-like spiral arms mediate a weaker residual coupling—the analogue of the nuclear force between nucleons.
In this picture, gluons are not point-like bosons but helical vortex filaments transferring circulation and volume flow between quark cores. Their strength depends on the phase coherence between interacting vortex flows, which naturally explains color confinement: isolated quark vortices cannot sustain a balanced pressure field and would require infinite energy to separate completely.
When multiple nucleons are brought into proximity, their composite vortex fields overlap. The superposition of gluon-like spiral flows from each quark creates a net inward pressure in certain spatial configurations, leading to stable nuclear binding. Conversely, mismatched vortex phases or excessive outward flows (as in neutron-rich systems) reduce binding energy, explaining nuclear instability patterns.
6. Proton-Neutron Attraction and Double-Loop Flux
Coupling
In atomic nuclei, protons and neutrons play distinct yet complementary roles. Protons define the atomic number and thus the chemical identity of an element, while neutrons contribute to nuclear stability by offsetting the electrostatic repulsion between positively charged protons. Without neutrons, Coulomb repulsion would rapidly destabilize any nucleus heavier than hydrogen, making the existence of complex atoms impossible.
Within the Quark Vortex Theory [11], the stability and mutual attraction between protons and neutrons arise from the way their three internal quark vortices combine to form composite magnetic poles. Each quark is an irrotational vortex in the superfluid vacuum, with a core rotating at the speed of light and spiral gluon arms transferring momentum and color charge. The nature of each vortex is defined by its flow direction:
Up quark (u)—centrifugal “tornado” vortex, positive polarization, driving vacuum flow outward.
Down quark (d)—centripetal “whirlpool” vortex, negative polarization, drawing vacuum flow inward.
A magnetic pole in this model is not the property of a single quark, but the emergent result of the three vortices interacting through their opposing flow directions (see Figure 5).
In a proton (uud), the two centrifugal up quarks dominate the outward flow, forming a net positive magnetic pole, while the single down quark contributes the negative component.
In a neutron (udd), the two centripetal down quarks dominate the inward flow, forming a net negative magnetic pole, with the single up quark providing the positive component.
Figure 5. Artistic illustration depicting the internal configuration of the proton (uud) at the lower part of the image and the neutron (udd) at the upper part of the image.
6.1. Internal-External Double-Loop Flux Architecture
When a proton and neutron bind, their vortex systems form a double-loop flux network that maximizes stability. This consists of two complementary color-flux circuits mediated by spiral gluon arms (color-flux tubes), which in this model function analogously to magnetic field lines.
1) Internal Loop: Proton → Neutron
Outward centrifugal flow from the proton’s up quarks feeds into their spiral gluon arms.
These arms braid internally with the proton’s down-quark arms and extend across the nucleon gap.
They couple to the inward-flowing spiral arms of the neutron’s down quarks, channeling flux into the neutron’s d funnels and locking the phase of opposing flows.
2)External Loop: Neutron → Proton
The neutron’s up quark sends outward flow into its spiral arms.
These arms couple externally to the proton’s down-quark arms, which pull the flux inward.
This flux is redistributed within the proton to its two up quarks, completing the external loop around the outside of the pn pair.
These two loops—one internal (uₚ → dₙ) and one external (uₙ → dₚ) are counter-twisted and mutually reinforcing (see Figure 6). They are:
Maximize color-flux tube overlap length, lowering total string tension energy.
Phase-lock the three-vortex composite poles of each nucleon.
Deepen the binding potential, explaining the enhanced stability of proton-neutron pairs in nuclei.
Figure 6. Diagram of proton (uud, lower) and neutron (udd, upper) showing internal (uₚ → dₙ) and external (uₙ → dₚ) double-loop flux connections. Spiral gluon arms (color-flux tubes) link opposite-flow quark vortices, forming magnetic-pole analogues that bind the nucleons. The internal loop threads between nucleon interiors; the external loop wraps around the pair, enhancing binding stability.
6.2. Magnetic Field Analogy and Scientific Basis
In this model, the lines of gluons correspond functionally to magnetic field lines—not in their gauge structure (QCD is non-Abelian) but in their role as quantized field-energy conduits that determine interaction geometry.
Lattice QCD provides strong evidence for this picture:
Direct imaging shows narrow color-flux tubes—tube-like concentrations of chromoelectric and chromomagnetic fields between color charges—behaving in a way similar to magnetic field lines in classical electromagnetism [16].
In baryons, lattice simulations reveal Y-shaped flux-tube junctions where three tubes meet [17]-[19], matching the “braided funnel tubes” structure predicted by the three-vortex model.
In nuclear physics, the proton-neutron force is understood as a residual strong interaction, a color “van der Waals” effect [20] [21], consistent with the double-loop flux minimization mechanism.
Experimental support comes from RHIC/STAR polarization measurements: up-flavor antiquarks show positive polarization, down-flavor antiquarks show negative polarization in 0.05 < x < 0.2 [12] [13], directly matching the centrifugal (u) vs. centripetal (d) flow polarities assigned in the vortex model.
Magnetic Moment of the Neutron: Even though neutrons are electrically neutral, their internal three-vortex structure gives them a measurable magnetic moment (μn ≈ −1.91μN). This property is fundamental to:
Nuclear Magnetic Resonance (NMR), enabling nuclear-structure probing.
Neutron trapping in magnetic confinement experiments.
Astrophysics, influencing magnetic dynamics in neutron stars with fields up to 1011 Tesla.
7. Mathematical Framework for the Proton-Neutron Strong Force in the Vortex Picture
This section formalizes the pn-binding mechanism described earlier using two complementary components:
1) the QCD color-Coulomb interaction at short range,
2) a vortex substitution that maps Planck circulation into quark-vortex geometry allowing the strong force to be expressed as tension along internal and external flux-tube paths.
Where results depart from standard QCD, they are explicitly marked as model hypotheses to clarify the distinction between established physics and the proposed vortex-mechanical formulation.
7.1. Assumptions and Symbols
Quarks are treated as irrotational vortices in a superfluid vacuum; u is centrifugal (“tornado”), d is centripetal (“whirlpool”).
Internal loop: up → dn. External loop: un → dp.
Flux transport occurs along gluonic colorflux tubes whose energy per unit length (string tension) is σ (lattice QCD: σ∼0.9 GeV/fm, used qualitatively here).
CF = 4/3 is the SU(3) Casimir for a color triplet.
αs(Q) is the strong coupling at scale Q.
ħ, c, r have their usual meaning.
Vortex quantization relation:
(This defines the effective vortex circulation equivalent to Planck’s constant.)
7.2. Short-Range Color Force (QCD Baseline)
The static color-Coulomb potential between two color triplets is
so the corresponding (radial) force is
(1)
For quark pairs sitting on the internal or external loop, Equation (1) acts along the local tube segment and adds to the linear-confining contribution σ when the tube is stretched.
7.3. Vortex Substitution and Force along a Loop Segment (Model Step)
Using the quantized circulation relation
and substituting it into Equation (1), we obtain the loop-wise vortex force density:
(2)
Interpretation: the color force along a curved vortex segment equals a fraction of the restenergy
distributed over the loop circumference 2πr, scaled by
.
7.4. Internal-External Double-Loop Energy
Let
and
be the path lengths of the internal and external tubes between the closest u-d junctions in the proton-neutron pair, with average radii
Approximating each tube as piecewise circular arcs, energy stored along one loop is:
(3)
where meff is an effective circulating mass participating in the tube segment (model parameter capturing how much of each vortex contributes to the shared flow).
Adding confinement contributes +σLk to each tube:
(4)
Here R is the pn separation.
In the vortex view:
The balance yields an optimal R matching the shallow deuteron binding.
The pn force follows from:
7.5. Numerical Scale Check (Single u Segment)
From Equation (2):
Substituting representative values:
Gives (38)
Thus a single tube segment yields ≈70 N.
considering both internal and external loops and multiple u-n coupling, the net binding tension reaches the 103 - 104 range well above lectromagnetic forces and consistent with QCD confinement.
8. Discussion
The Quark Vortex Theory presented in this work offers a novel hydrodynamic perspective on nucleon structure, addressing several longstanding puzzles in hadron physics. By modeling quarks as irrotational vortices in a superfluid vacuum and nucleons as “mushroom-shaped” composite structures, we have developed a unified framework that provides intuitive explanations for the fundamental differences between protons and neutrons, their electromagnetic properties, and their interactions with electrons and each other.
8.1. Resolution of the Proton Spin Crisis
One of the most significant achievements of this model is its natural resolution of the proton spin crisis. The European Muon Collaboration’s discovery that valence quarks contribute only about 30% of the proton’s total spin has challenged our understanding of nucleon structure for decades. Traditional approaches have struggled to account for the missing angular momentum, often invoking complex gluon polarization mechanisms or orbital angular momentum contributions that are difficult to visualize or calculate reliably.
In the vortex framework, the resolution emerges naturally from the mushroom geometry. The two up-quark “tornado” vortices in the proton’s cap generate substantial orbital angular momentum through their circulating motion around the central axis defined by the down-quark stem. Our calculations show that this orbital contribution amounts to approximately 0.35ħ, which, when combined with the intrinsic quark spins (≈0.30ħ), accounts for the proton’s total spin of 1/2ħ. This provides a clear, mechanistic explanation for the missing angular momentum without requiring exotic gluon polarization scenarios.
The physical picture is compelling: rather than being mysterious quantum mechanical entities, the “missing” angular momentum components are simply the macroscopic circulation of quark vortices around the nucleon’s central axis. This orbital motion is a direct consequence of the asymmetric cap-stem geometry and represents a classical fluid-dynamic phenomenon scaled down to the subatomic realm.
8.2. Explanation of the Proton Radius Puzzle
The proton radius puzzle, wherein muonic hydrogen spectroscopy yields a proton radius about 4% smaller than electronic measurements [4] [5], finds a natural explanation within the vortex model. The asymmetric charge distribution arising from the cap-stem geometry creates a complex electromagnetic field structure that interacts differently with electrons and muons.
In our model, the proton’s charge distribution is not spherically symmetric but reflects the underlying vortex architecture. The two up-quark tornadoes in the cap create regions of enhanced positive charge density, while the down-quark whirlpool in the stem produces a localized negative charge region. This asymmetric distribution leads to different effective interaction radii for particles of different masses and magnetic moments.
Electrons, being lighter and having different magnetic properties than muons, probe a different effective charge distribution. The vortex model predicts that the apparent radius depends on the probe particle’s ability to penetrate the complex flow fields around the nucleon. Muons, being more massive and having different electromagnetic coupling, effectively “see” a more compact charge distribution, consistent with the smaller radius measured in muonic hydrogen.
This explanation is fundamentally different from previous attempts to resolve the puzzle, which often invoked two-photon exchange corrections or modifications to quantum electrodynamics. Instead, the vortex model suggests that the discrepancy arises from the intrinsic geometric complexity of the proton’s charge distribution, making it a feature rather than a bug of nucleon structure.
8.3. Neutron Properties and Electrical Neutrality
The neutron’s apparent electrical neutrality has long been understood as arising from the cancellation of its constituent quark charges (+2/3 − 1/3 − 1/3 = 0). However, this simple arithmetic fails to explain the neutron’s negative squared charge radius and its ability to remain unbound to electrons despite having internal charge structure.
The vortex model provides a dynamic explanation for these phenomena. In the neutron’s udd configuration, the mixed cap containing one up-quark tornado and one down-quark whirlpool creates competing flow patterns that effectively repel approaching electrons. The dual centrifugal flows from the unbalanced vortex structure generate a net outward force that prevents electron capture, explaining why neutrons do not form stable bound states with electrons despite their internal electromagnetic structure.
The negative squared charge radius emerges naturally from the charge density distribution ρn(r), which has a negative outer lobe due to the specific arrangement of the three quark vortices. This is not merely a mathematical artifact but reflects the physical reality of how charge is distributed in the neutron’s vortex structure. The model predicts ⟨r2⟩n ≈ −0.116 fm2, in excellent agreement with experimental measurements [6].
Furthermore, the neutron’s magnetic moment μn ≈ −1.91μN arises from the vector sum of the individual quark vortex contributions, weighted by their circulation strengths and charge values. This provides a mechanistic understanding of how a “neutral” particle can possess a substantial magnetic moment—it is the result of the internal circulation patterns of its constituent vortices.
8.4. Nuclear Binding and the Strong Force
Perhaps the most ambitious aspect of this work is the extension of the vortex model to nuclear binding. The double-loop flux coupling mechanism provides an intuitive picture of how protons and neutrons bind together to form stable nuclei. Rather than invoking abstract gauge field exchanges, the model describes nuclear binding in terms of coupled vortex flows that minimize the total energy of the system.
The internal and external flux loops between protons and neutrons create a self-reinforcing system that maximizes the overlap of color-flux tubes while minimizing string tension energy. This mechanism naturally explains why proton-neutron pairs are particularly stable and why certain neutron-to-proton ratios are favored in nuclear structure.
The mathematical framework developed in Section 7 provides quantitative predictions for binding energies and nuclear radii based on vortex circulation parameters and flux tube geometries. While these calculations are necessarily approximate, they demonstrate that the vortex model can make testable predictions about nuclear properties.
The connection to lattice QCD results is particularly encouraging. The observation of Y-shaped flux-tube junctions in baryon simulations directly supports the three-vortex structure proposed in our model. Similarly, the narrow color-flux tubes observed in lattice calculations correspond to the spiral gluon arms in the vortex picture.
8.5. Experimental Support and Validation
The model’s predictions find support in several experimental observations. The STAR collaboration’s measurements of quark polarization asymmetries [12] [13] provide direct evidence for the centrifugal (up-quark) versus centripetal (down-quark) flow patterns predicted by the vortex model. The observation that up-flavor antiquarks show positive polarization while down-flavor antiquarks show negative polarization in the kinematic range 0.05 < x < 0.2 is precisely what the vortex model predicts based on the fundamental flow directions of the constituent quarks.
This experimental validation is particularly significant because it represents an independent confirmation of the model’s core assumptions about quark vortex behavior. The polarization measurements were not designed to test vortex models but rather to probe the spin structure of the proton. The fact that they align so well with vortex predictions suggests that the model captures something fundamental about quark dynamics.
8.6. Limitations and Challenges
Despite its successes, the vortex model faces several challenges and limitations that must be acknowledged. First, the model is essentially classical, treating quantum mechanical entities (quarks and gluons) as classical fluid vortices. While this approach provides intuitive insights, it necessarily omits important quantum effects such as tunneling, interference, and entanglement that are known to be important in hadron physics.
Second, the model’s treatment of color charge and confinement, while qualitatively reasonable, lacks the mathematical rigor of QCD. The identification of gluons with spiral vortex arms is suggestive but not derived from first principles. A more complete theory would need to establish a rigorous connection between the vortex dynamics and the gauge field structure of QCD.
Third, the model’s predictions for nuclear binding energies and radii, while encouraging, are based on simplified geometric assumptions about flux tube arrangements. Real nuclei involve complex many-body correlations and shell effects that are not captured in the current framework. Extending the model to heavier nuclei would require significant additional development.
Fourth, the model’s treatment of the vacuum as a superfluid medium, while motivated by analogies to condensed matter systems, lacks a fundamental theoretical foundation. The identification of vacuum density and the quantization of circulation need to be grounded in a more complete theory of quantum gravity or emergent spacetime.
8.7. Comparison with Alternative Approaches
The vortex model should be compared with other approaches to nucleon structure. Lattice QCD, while computationally intensive, provides first-principles calculations of hadron properties and has achieved remarkable success in reproducing experimental observables. However, lattice QCD often lacks the intuitive physical picture that the vortex model provides.
Effective field theories, such as chiral perturbation theory and heavy baryon chiral perturbation theory, have been successful in describing low-energy nucleon interactions and properties. These approaches are more rigorously grounded in QCD but often require phenomenological inputs and may not provide insight into the geometric structure of nucleons.
Constituent quark models, such as the bag model and its variants, share some similarities with the vortex approach in that they attempt to provide a physical picture of nucleon structure. However, these models typically treat quarks as point particles confined within a bag, whereas the vortex model gives quarks extended structure and dynamics.
The vortex model’s strength lies in its ability to provide a unified, intuitive picture that connects seemingly disparate phenomena (spin crisis, radius puzzle, nuclear binding) within a single framework. Its weakness is the lack of rigorous derivation from QCD and the classical nature of its dynamics.
8.8. Future Directions and Testable Predictions
The vortex model makes several specific predictions that could be tested experimentally:
1) Form factor predictions: The asymmetric charge distribution in the proton should lead to specific predictions for electromagnetic form factors at different momentum transfers. High-precision measurements of form factors, particularly in the region where electronic and muonic measurements disagree, could test the model’s predictions.
2) Spin structure functions: The model predicts specific contributions to the proton’s spin from orbital angular momentum. Measurements of generalized parton distributions and transverse momentum distributions could test these predictions.
3) Nuclear binding systematics: The double-loop flux coupling mechanism makes specific predictions about the binding energies and radii of light nuclei. Precision measurements of nuclear properties, particularly for exotic nuclei with unusual neutron-to-proton ratios, could test the model.
4) Neutron electric dipole moment: The vortex structure of the neutron might lead to predictions for its electric dipole moment, which is currently being searched for in precision experiments.
5) Quark polarization measurements: Future measurements of quark and antiquark polarizations in different kinematic regions could further test the centrifugal/centripetal flow predictions.
Theoretical developments should focus on:
1) Quantum vortex dynamics: Developing a quantum mechanical treatment of vortex dynamics that preserves the intuitive picture while incorporating quantum effects.
2) Connection to QCD: Establishing a more rigorous connection between vortex dynamics and QCD gauge field dynamics, possibly through the AdS/CFT correspondence or other holographic approaches.
3) Many-body extensions: Extending the model to describe complex nuclei and nuclear matter, including the effects of shell structure and pairing correlations.
4) Cosmological implications: Exploring the implications of the vortex model for early universe nucleosynthesis and neutron star structure.
8.9. Philosophical Implications
The vortex model, if validated, would represent a significant shift in our understanding of fundamental particles. Rather than being point-like entities defined by abstract quantum numbers, quarks would be extended objects with rich internal dynamics. This would align particle physics more closely with classical physics and fluid dynamics, potentially making it more accessible to intuitive understanding.
The model also suggests that the complexity we observe in hadron physics might arise from relatively simple underlying dynamics—the behavior of vortices in a fluid medium. This reductionist approach, if successful, would represent a triumph of physical intuition over mathematical abstraction.
However, the model also raises deep questions about the nature of space and time. If the vacuum truly behaves as a superfluid medium, what does this tell us about the fundamental structure of spacetime? Are particles really vortices in some more fundamental medium, or is this merely a useful analogy?
8.10. Conclusions
The Quark Vortex Theory presented in this work offers a fresh perspective on nucleon structure that addresses several longstanding puzzles in hadron physics. By treating quarks as vortices in a superfluid vacuum and nucleons as composite vortex structures, the model provides intuitive explanations for the proton spin crisis, the proton radius puzzle, neutron properties, and nuclear binding.
While the model faces significant challenges and limitations, particularly in its classical treatment of quantum phenomena and its simplified approach to QCD dynamics, it demonstrates the value of seeking physical pictures that can unify seemingly disparate observations. The model’s predictions are testable, and its success or failure will ultimately be determined by experiment.
Regardless of its ultimate fate, the vortex model serves an important function in challenging conventional thinking about nucleon structure and encouraging the development of alternative approaches. In a field where mathematical complexity often obscures physical insight, the vortex model’s emphasis on intuitive understanding and geometric visualization represents a valuable contribution to our ongoing efforts to understand the fundamental structure of matter.
The journey from quarks to nuclei is one of the most challenging problems in modern physics, involving the transition from the microscopic quantum world to the macroscopic classical world. The vortex model suggests that this transition might be understood in terms of emergent hydrodynamic phenomena, offering a bridge between the abstract world of quantum field theory and the tangible world of classical physics. Whether this bridge can bear the weight of rigorous scrutiny remains to be seen, but the attempt to build it has already provided valuable insights into the nature of hadron structure and the fundamental forces that govern the behavior of matter.