nucleon
Enable an AI agent to identify a proton or neutron as a nucleon, record its physical context, and judge which descriptions, measurements, and transformations apply.
Bundle → Layer → Finding → Questions Filled
5 bundles · 9 layers · 15 findings · 28 questions
Species and quantum identity Establishes which nucleon is represented and the quantum labels that identify it.
Proton-neutron membership
Defines category membership and its boundaries against neighbouring particle and nuclear categories.
Species assignment
A nucleon assignment resolves to proton or neutron and distinguishes category membership from membership in a nucleus.
- What evidence identifies this nucleon as a proton or neutron? definition
- Does the record describe an individual nucleon, a one-proton nucleus, or a larger nuclear system? boundary
Quantum labels and spin state
Separates intrinsic particle properties from prepared states and approximate symmetry labels.
Intrinsic versus prepared properties
Charge, baryon number, and intrinsic spin identify the particle, while polarization specifies its state; isospin assignments require an explicit convention.
- Which intrinsic quantum labels are assigned, and do they agree with the selected nucleon species? definition
- How was polarization determined, and relative to which axis or basis? measurement
- If isospin is used, which projection convention and symmetry-breaking limitations apply? boundary
Composite structure and probes Connects quark and gluon descriptions to the observables that resolve nucleon structure.
Quark and gluon description
Records net flavour content while retaining the scale dependence of more detailed constituent descriptions.
Valence content and description scale
The uud and udd assignments encode valence content; descriptions of sea quarks, gluons, and momentum distributions require additional theoretical and scale information.
- Is the description limited to net valence flavour, or does it include resolved quark and gluon distributions? definition
- Which resolution scale, theoretical framework, and source support the stated internal structure? provenance
Electromagnetic structure
Distinguishes magnetic moments, form factors, and radius definitions.
Observable-specific size and coupling
Nucleon size is inferred through specified observables, and zero net neutron charge does not imply absent electromagnetic structure.
- Which form factor, magnetic moment, or radius definition is being reported? measurement
- What experiment, extraction method, uncertainty, and momentum-transfer range support the value? provenance
- Would interpreting this value as a positive geometric radius misrepresent the observable, particularly for neutron mean-square charge radius? boundary
Free and bound description Records the environment and kinematic assumptions needed to describe the nucleon.
Nuclear embedding
Connects a bound nucleon to its host nucleus and the many-body description being used.
Host and state assignment
Nuclear membership and orbital or configuration assignments depend on the host state and nuclear model; identical nucleons need not have individually trackable identities.
- Is the nucleon free or bound, and which nucleus and nuclear state provide its context? definition
- What nuclear model supports any orbital, occupancy, or individual-nucleon assignment? provenance
- Does the proposed record incorrectly treat indistinguishable nucleons as persistently labelled classical particles? boundary
Kinematics and binding
Separates reference rest mass from context-dependent energy and momentum assignments.
Energy-momentum interpretation
Kinematic records identify the frame and distinguish free rest mass, inferred bound-nucleon quantities, effective mass, and nuclear separation energy.
- In which frame and by which measurement or calculation were energy and momentum assigned? measurement
- Is the quoted mass or energy a free rest mass, model-dependent effective quantity, or property of a nuclear removal process? boundary
Interactions and transformations Describes how a nucleon scatters, participates in nuclear reactions, and changes species through weak processes.
Scattering and nuclear reactions
Records reaction partners, energy regimes, channels, and the evidence supporting predicted outcomes.
Channel and interaction regime
Elastic scattering, inelastic excitation, capture, and particle production require different kinematic and interaction descriptions.
- Which initial particles or nuclear systems, collision energy, and final channel define the process? definition
- Which measured cross section or validated calculation supports the predicted outcome in this energy range? provenance
- Does the proposed channel satisfy the applicable conservation laws and energy threshold? action
Weak conversion and stability
Distinguishes free-neutron decay from environment-dependent proton-neutron conversion.
Context-dependent conversion
Free neutrons undergo beta decay; nuclear binding and total-system energetics determine whether corresponding conversions are available in a nucleus.
- Is the proposed process free-neutron beta decay, nuclear beta decay, electron capture, or another specified weak reaction? definition
- Do the complete initial and final systems make the conversion energetically possible, including required leptons? action
- Which measurement and physical context support any lifetime, branching fraction, or stability claim? provenance
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Check these first
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these check these first hold for the sense of nucleon this model covers, and on what evidence? provenance
Kinds and varieties
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these kinds and varieties hold for the sense of nucleon this model covers, and on what evidence? provenance
Identifiers and schemes
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these identifiers and schemes hold for the sense of nucleon this model covers, and on what evidence? provenance
Real-world use
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these real-world use hold for the sense of nucleon this model covers, and on what evidence? provenance
Typical measurements
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these typical measurements hold for the sense of nucleon this model covers, and on what evidence? provenance
Failure modes and hazards
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these failure modes and hazards hold for the sense of nucleon this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of nucleon this model covers, and on what evidence? provenance
Classifiers Filled
- Family
- Thing Registry
- Category
- Physical world and living systems
- Entry kind
- thing
- Plane
- PHY
- Domain
- PHY.OBJ
What it is Filled
A nucleon is a proton or neutron, a composite spin-1/2 baryon that participates in the strong interaction and constitutes ordinary atomic nuclei.
In scope
- Proton or neutron identity and the properties shared by nucleons
- Quark and gluon structure and the limits of constituent descriptions
- Free, nuclear-bound, and scattering states
- Nucleon interactions, transformations, and conservation constraints
- Measurement context and uncertainty for nucleon properties
Out of scope
- Whole-nucleus composition, collective structure, and isotope classification
- Atomic electron configurations and chemical bonding
- Quarks and gluons treated as independently modelled particle categories
- Antinucleons as physical instances, except as comparison or reaction partners
- Other baryons and excited baryon resonances as independent particle categories
- Accelerators, detectors, and experimental facilities as equipment
Why it exists Filled
Enable an AI agent to identify a proton or neutron as a nucleon, record its physical context, and judge which descriptions, measurements, and transformations apply.
Distinguishing features Filled
- A nucleon is a proton or neutron; membership in the broader baryon category alone is insufficient.
- A proton has electric charge +1 e and a neutron has charge 0 e; electrical neutrality does not make a neutron an elementary neutral particle.
- A nucleon is a composite spin-1/2 baryon with baryon number +1, distinguishing it from leptons, mesons, and antinucleons.
- Proton and neutron valence-quark content is uud and udd respectively; these labels specify net flavour content without exhausting the quark and gluon structure.
- A nucleon can exist outside a nucleus, while a nucleus is a nuclear system; an ordinary hydrogen nucleus is the special case consisting of one proton.
What robots and AI may and may not do Filled
Must not
- Present speculative nucleon physics as established fact.
- Confuse nucleons with other particles in data or teaching material.
Only with a human decision
- Publishing nuclear data used in safety-critical calculations.
May
- Explain nucleon properties and roles in nuclei from established physics.
- Use nucleon numbers to describe isotopes in calculations.
Moral aspects Filled
- Nuclear knowledge underlies both energy and weapons, and its applications carry great moral weight.
Who is affected
- Students
- Researchers
- Nuclear safety engineers
Owners Filled
Steward
Nobody owns it; it is a natural constituent of matter.
Master systems
- Nuclear data libraries
Links to other meta-models Filled
parent
- Q4044799 - registry parent class
What else AI and robots need to interact with it Filled
Identity and identifiers required Filled
- Vercy registry: vr.tr.nucleon
- Wikidata: Q102165 (https://www.wikidata.org/wiki/Q102165)
Direct properties required Filled
- Nucleon species: proton | neutron
- Electric charge: e; proton +1, neutron 0
- Intrinsic spin: spin quantum number s = 1/2
- Polarization: spin density matrix or polarization vector relative to a specified basis
- Baryon number: +1
- Rest mass: MeV/c²; species-specific reference value with source and uncertainty
- Physical context: free | nuclear-bound | scattering | other explicitly specified many-body context
- Nuclear host: reference to a nucleus and its state, when applicable
- Four-momentum: energy in MeV and momentum in MeV/c, with reference frame and inference method
- Magnetic moment: nuclear magnetons, with sign and species
- Spatial-structure observable: specified form factor or radius convention; fm or fm² where appropriate
Recognition not applicable Not applicable
Not applicable
An individual nucleon has no directly visible identifying features and requires instrumental detection to characterize it.
Capabilities and actions required Filled
- Classify a candidate as a proton or neutron using charge, baryon identity, and experimental evidence.
- Select a free-particle or nuclear many-body description appropriate to the physical context and probe scale.
- Construct and check a proposed reaction channel using charge, baryon-number, energy, momentum, and angular-momentum accounting.
- Relate measured scattering or magnetic observables to nucleon structure under an explicit interpretation model.
- Assess whether a species-changing process is energetically available in the recorded free or bound state.
- Record preparation, polarization, scattering, or detection procedures through their associated experimental systems.
Hazards and failure modes required Filled
- Energetic proton or neutron radiation can damage living tissue and electronic equipment.
- Confusing proton and neutron behavior can produce incorrect assessments of radiation shielding and nuclear processes.
Standards and interfaces not applicable Not applicable
Not applicable
No standard, law or official classification directly governs a nucleon itself independently of its experimental or technological context.
Context of use required Filled
- Nucleons occur as protons and neutrons in atomic nuclei and can also be studied outside nuclei in particle beams and experiments.
- They are used in descriptions of nuclear structure, isotopes, nuclear reactions and the composition of ordinary matter.
Sources Filled
- Wikidata item Q102165: nucleon - identity and sense of the item
- Wikipedia: Nucleon - general description of the item
Open questions
- Does the existing Vercy catalogue already contain a nucleon model or proton and neutron models to which this entry should link?
- Which authoritative reference values, uncertainty conventions, and experimental determinations should supply masses, magnetic moments, radii, and the free-neutron lifetime?
- Which nuclear frameworks should be supported for bound-state assignments, effective masses, and removal energies, and how should their incompatible conventions be exposed?
- Where should the catalogue place the boundary between a nucleon undergoing excitation and an independently represented baryon resonance?
- Which probe-energy ranges and applications must the first researched model support, determining how much form-factor, parton, and reaction-channel detail is necessary?
Machine files
Provenance
thing registry research (pass 2) · unreviewed
Built from: models/things/publications/thing-q102165/spec.json