{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.nucleon","code":"thing-q102165","url":"https://ver.cy/models/thing/q102165/","name":"nucleon","alternateNames":[],"kind":"thing","status":"published","version":"0.1.0-research.1","language":"en","classifiers":{"family":"Thing Registry","category":"Physical world and living systems","entryKind":"thing","plane":"PHY","domain":["PHY.OBJ"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"A nucleon is a proton or neutron, a composite spin-1/2 baryon that participates in the strong interaction and constitutes ordinary atomic nuclei.","purpose":"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.","scope":{"in":["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":["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"],"boundaries":[]},"distinguishingFeatures":["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."],"structure":{"bundles":[{"id":"species-and-quantum-identity","name":"Species and quantum identity","description":"Establishes which nucleon is represented and the quantum labels that identify it.","layers":[{"id":"proton-neutron-membership","name":"Proton-neutron membership","description":"Defines category membership and its boundaries against neighbouring particle and nuclear categories.","findings":[{"id":"species-assignment","name":"Species assignment","description":"A nucleon assignment resolves to proton or neutron and distinguishes category membership from membership in a nucleus.","questions":[{"text":"What evidence identifies this nucleon as a proton or neutron?","id":"species-assignment-q01","kind":"definition"},{"text":"Does the record describe an individual nucleon, a one-proton nucleus, or a larger nuclear system?","id":"species-assignment-q02","kind":"boundary"}]}]},{"id":"quantum-labels-and-spin-state","name":"Quantum labels and spin state","description":"Separates intrinsic particle properties from prepared states and approximate symmetry labels.","findings":[{"id":"intrinsic-versus-prepared-properties","name":"Intrinsic versus prepared properties","description":"Charge, baryon number, and intrinsic spin identify the particle, while polarization specifies its state; isospin assignments require an explicit convention.","questions":[{"text":"Which intrinsic quantum labels are assigned, and do they agree with the selected nucleon species?","id":"intrinsic-versus-prepared-properties-q01","kind":"definition"},{"text":"How was polarization determined, and relative to which axis or basis?","id":"intrinsic-versus-prepared-properties-q02","kind":"measurement"},{"text":"If isospin is used, which projection convention and symmetry-breaking limitations apply?","id":"intrinsic-versus-prepared-properties-q03","kind":"boundary"}]}]}]},{"id":"composite-structure-and-probes","name":"Composite structure and probes","description":"Connects quark and gluon descriptions to the observables that resolve nucleon structure.","layers":[{"id":"quark-gluon-description","name":"Quark and gluon description","description":"Records net flavour content while retaining the scale dependence of more detailed constituent descriptions.","findings":[{"id":"valence-content-and-description-scale","name":"Valence content and description scale","description":"The uud and udd assignments encode valence content; descriptions of sea quarks, gluons, and momentum distributions require additional theoretical and scale information.","questions":[{"text":"Is the description limited to net valence flavour, or does it include resolved quark and gluon distributions?","id":"valence-content-and-description-scale-q01","kind":"definition"},{"text":"Which resolution scale, theoretical framework, and source support the stated internal structure?","id":"valence-content-and-description-scale-q02","kind":"provenance"}]}]},{"id":"electromagnetic-structure","name":"Electromagnetic structure","description":"Distinguishes magnetic moments, form factors, and radius definitions.","findings":[{"id":"observable-specific-size-and-coupling","name":"Observable-specific size and coupling","description":"Nucleon size is inferred through specified observables, and zero net neutron charge does not imply absent electromagnetic structure.","questions":[{"text":"Which form factor, magnetic moment, or radius definition is being reported?","id":"observable-specific-size-and-coupling-q01","kind":"measurement"},{"text":"What experiment, extraction method, uncertainty, and momentum-transfer range support the value?","id":"observable-specific-size-and-coupling-q02","kind":"provenance"},{"text":"Would interpreting this value as a positive geometric radius misrepresent the observable, particularly for neutron mean-square charge radius?","id":"observable-specific-size-and-coupling-q03","kind":"boundary"}]}]}]},{"id":"free-and-bound-description","name":"Free and bound description","description":"Records the environment and kinematic assumptions needed to describe the nucleon.","layers":[{"id":"nuclear-embedding","name":"Nuclear embedding","description":"Connects a bound nucleon to its host nucleus and the many-body description being used.","findings":[{"id":"host-and-state-assignment","name":"Host and state assignment","description":"Nuclear membership and orbital or configuration assignments depend on the host state and nuclear model; identical nucleons need not have individually trackable identities.","questions":[{"text":"Is the nucleon free or bound, and which nucleus and nuclear state provide its context?","id":"host-and-state-assignment-q01","kind":"definition"},{"text":"What nuclear model supports any orbital, occupancy, or individual-nucleon assignment?","id":"host-and-state-assignment-q02","kind":"provenance"},{"text":"Does the proposed record incorrectly treat indistinguishable nucleons as persistently labelled classical particles?","id":"host-and-state-assignment-q03","kind":"boundary"}]}]},{"id":"kinematics-and-binding","name":"Kinematics and binding","description":"Separates reference rest mass from context-dependent energy and momentum assignments.","findings":[{"id":"energy-momentum-interpretation","name":"Energy-momentum interpretation","description":"Kinematic records identify the frame and distinguish free rest mass, inferred bound-nucleon quantities, effective mass, and nuclear separation energy.","questions":[{"text":"In which frame and by which measurement or calculation were energy and momentum assigned?","id":"energy-momentum-interpretation-q01","kind":"measurement"},{"text":"Is the quoted mass or energy a free rest mass, model-dependent effective quantity, or property of a nuclear removal process?","id":"energy-momentum-interpretation-q02","kind":"boundary"}]}]}]},{"id":"interactions-and-transformations","name":"Interactions and transformations","description":"Describes how a nucleon scatters, participates in nuclear reactions, and changes species through weak processes.","layers":[{"id":"scattering-and-nuclear-reactions","name":"Scattering and nuclear reactions","description":"Records reaction partners, energy regimes, channels, and the evidence supporting predicted outcomes.","findings":[{"id":"channel-and-interaction-regime","name":"Channel and interaction regime","description":"Elastic scattering, inelastic excitation, capture, and particle production require different kinematic and interaction descriptions.","questions":[{"text":"Which initial particles or nuclear systems, collision energy, and final channel define the process?","id":"channel-and-interaction-regime-q01","kind":"definition"},{"text":"Which measured cross section or validated calculation supports the predicted outcome in this energy range?","id":"channel-and-interaction-regime-q02","kind":"provenance"},{"text":"Does the proposed channel satisfy the applicable conservation laws and energy threshold?","id":"channel-and-interaction-regime-q03","kind":"action"}]}]},{"id":"weak-conversion-and-stability","name":"Weak conversion and stability","description":"Distinguishes free-neutron decay from environment-dependent proton-neutron conversion.","findings":[{"id":"context-dependent-conversion","name":"Context-dependent conversion","description":"Free neutrons undergo beta decay; nuclear binding and total-system energetics determine whether corresponding conversions are available in a nucleus.","questions":[{"text":"Is the proposed process free-neutron beta decay, nuclear beta decay, electron capture, or another specified weak reaction?","id":"context-dependent-conversion-q01","kind":"definition"},{"text":"Do the complete initial and final systems make the conversion energetically possible, including required leptons?","id":"context-dependent-conversion-q02","kind":"action"},{"text":"Which measurement and physical context support any lifetime, branching fraction, or stability claim?","id":"context-dependent-conversion-q03","kind":"provenance"}]}]}]},{"id":"evidence-and-external-alignment","name":"Evidence and external alignment","description":"What the world already says about this thing, gathered so the model can be checked against it.","layers":[{"id":"reported-evidence","name":"Reported evidence","description":"Findings from the breadth pass, kept separate from the structural claims.","findings":[{"id":"evidence-confidence-notes","name":"Check these first","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these check these first hold for the sense of nucleon this model covers, and on what evidence?","id":"evidence-confidence-notes-q01","kind":"provenance"}]},{"id":"evidence-kinds","name":"Kinds and varieties","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these kinds and varieties hold for the sense of nucleon this model covers, and on what evidence?","id":"evidence-kinds-q01","kind":"provenance"}]},{"id":"evidence-identifiers","name":"Identifiers and schemes","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these identifiers and schemes hold for the sense of nucleon this model covers, and on what evidence?","id":"evidence-identifiers-q01","kind":"provenance"}]},{"id":"evidence-real-world-use","name":"Real-world use","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these real-world use hold for the sense of nucleon this model covers, and on what evidence?","id":"evidence-real-world-use-q01","kind":"provenance"}]},{"id":"evidence-measurements","name":"Typical measurements","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these typical measurements hold for the sense of nucleon this model covers, and on what evidence?","id":"evidence-measurements-q01","kind":"provenance"}]},{"id":"evidence-failure-modes-and-hazards","name":"Failure modes and hazards","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these failure modes and hazards hold for the sense of nucleon this model covers, and on what evidence?","id":"evidence-failure-modes-and-hazards-q01","kind":"provenance"}]},{"id":"evidence-neighbours","name":"Neighbouring kinds and how to tell them apart","description":"Recalled without web access and unsourced; every item is a lead to verify.","questions":[{"text":"Which of these neighbouring kinds and how to tell them apart hold for the sense of nucleon this model covers, and on what evidence?","id":"evidence-neighbours-q01","kind":"provenance"}]}]}]}]},"agentConduct":{"may":["Explain nucleon properties and roles in nuclei from established physics.","Use nucleon numbers to describe isotopes in calculations."],"mustNot":["Present speculative nucleon physics as established fact.","Confuse nucleons with other particles in data or teaching material."],"requiresHuman":["Publishing nuclear data used in safety-critical calculations."]},"ethics":{"considerations":["Nuclear knowledge underlies both energy and weapons, and its applications carry great moral weight."],"affectedParties":["Students","Researchers","Nuclear safety engineers"]},"owners":{"steward":"Nobody owns it; it is a natural constituent of matter.","roles":[],"masterSystems":["Nuclear data libraries"]},"relations":[{"target":"Q4044799","type":"parent","note":"registry parent class"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.nucleon","Wikidata: Q102165 (https://www.wikidata.org/wiki/Q102165)"]},"properties":{"applicability":"required","items":["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":{"applicability":"not-applicable","items":[]},"capabilities":{"applicability":"required","items":["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":{"applicability":"required","items":["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."]},"interfaces":{"applicability":"not-applicable","items":[]},"context":{"applicability":"required","items":["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":[{"title":"Wikidata item Q102165: nucleon","url":"https://www.wikidata.org/wiki/Q102165","note":"identity and sense of the item"},{"title":"Wikipedia: Nucleon","url":"https://en.wikipedia.org/wiki/Nucleon","note":"general description of the item"}],"openQuestions":["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?"],"resources":{"spec":"/models/things/publications/thing-q102165/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q102165/spec.json"],"providers":["Codex"],"researchStatus":"unreviewed","generatedAt":"2026-09-07T14:10:57Z","builder":"tools/build_cards.py@1.0.0"},"completeness":{"sections":{"classifiers":"filled","whatItIs":"filled","purpose":"filled","distinguishingFeatures":"filled","structure":"filled","agentConduct":"filled","ethics":"filled","owners":"filled","relations":"filled","interaction.identity":"filled","interaction.properties":"filled","interaction.recognition":"not-applicable","interaction.capabilities":"filled","interaction.hazards":"filled","interaction.interfaces":"not-applicable","interaction.context":"filled","sources":"filled"},"notes":{"_gate":"Published through the thing publication gate 1.0 on 2026-10-07T10:10:25+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass","interaction.interfaces":"No standard, law or official classification directly governs a nucleon itself independently of its experimental or technological context.","interaction.recognition":"An individual nucleon has no directly visible identifying features and requires instrumental detection to characterize it."},"score":1.0}}