subatomic particle
Enable an AI agent to identify a subatomic particle species or candidate, assess its physical state and evidential status, and determine which interactions, measurements or manipulations are physically applicable.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
recalled by Codex without web access - no source was read
Researched by: Codex
Purpose and description
Enable an AI agent to identify a subatomic particle species or candidate, assess its physical state and evidential status, and determine which interactions, measurements or manipulations are physically applicable.
A subatomic particle is an elementary or composite physical entity studied at the level of atomic constituents and their interactions, including electrons, quarks, photons, protons and neutrons.
It can be Classify a species or candidate using composition, quantum numbers and available evidence.; Check whether a proposed production, scattering or decay channel is compatible with kinematics and applicable conservation laws.; Compare competing particle identifications against measured signatures and stated uncertainties.; Determine whether a specified preparation permits transport, deflection, trapping or state measurement.; Reconstruct parent-particle hypotheses from decay products while retaining ambiguity and missing information.; Update property estimates and identification status when new measurements or revised interpretations become available..
Distinguishing features
An entity can qualify as subatomic without having a measurable geometric diameter; classification must not depend on a literal size comparison with an atom.
An elementary-particle classification requires distinguishing absence of observed internal structure from proof that no deeper structure exists.
A composite particle such as a proton has constituent structure and bound-state properties; it must not be assigned elementary status merely because it appears as one detected particle.
A detector track, calorimeter deposit or missing-momentum signature is evidence for a particle hypothesis, not itself a particle.
A particle species, a prepared quantum state and an individual detection event must remain distinguishable; identical particles do not acquire intrinsic serial identities from event labels.
Scope
+ Elementary particle species and composite subatomic particles, including protons and neutrons
+ Particle-antiparticle relationships and conserved or approximately conserved quantum numbers
+ Intrinsic properties, quantum states and preparation-dependent quantities
+ Production, scattering, transformation and decay processes
+ Evidence connecting observed detector signatures to particle hypotheses
- Whole atoms, molecules and bulk materials as independently modelled systems
- Detector, accelerator and experimental apparatus design and operation
- Quantum fields and physical theories as standalone mathematical models
- Condensed-matter quasiparticles treated as collective excitations of a material
- Complete nuclear structure and isotope catalogues, while retaining links to nuclear constituents
Characteristics
- Composition class
- elementary within the stated framework | composite | unresolved Determines whether constituent structure must be represented and qualifies the strength of an elementary-particle claim.
- Particle family
- lepton, quark, gauge boson, scalar boson, hadron or explicitly specified alternative; classification framework required Supports recognition without assuming that every candidate belongs to an established family.
- Rest mass
- eV/c², MeV/c² or GeV/c²; value, uncertainty or limit with mass definition Constrains kinematics and identification while accommodating bounds and definition-dependent values.
- Intrinsic spin
- spin quantum number j, with angular momentum expressed in units of ℏ Constrains quantum statistics, allowed states and interaction patterns.
- Electric charge
- multiples of the elementary charge e Constrains electromagnetic response and possible detector signatures.
- Additional quantum numbers
- named quantum numbers or symmetry representations, with conventions and conservation conditions Distinguishes species and constrains reactions without treating every label as universally conserved.
- Antiparticle relationship
- distinct antiparticle | self-conjugate | unresolved, linked to species Supports charge-conjugation comparisons and interpretation of production or annihilation processes.
- Lifetime or decay width
- proper mean lifetime in s or decay width in eV; uncertainty, bound or qualified stability statement Determines whether direct transport, displaced decay or indirect reconstruction is relevant.
- Four-momentum
- energy in eV and momentum components in eV/c, with reference frame and uncertainty Enables conservation checks and separates preparation-dependent motion from intrinsic mass.
- Spin and coherence state
- polarization, helicity, state amplitudes or density operator, with basis and preparation context Supports predictions that depend on the prepared state rather than species alone.
- Identification status
- established species | hypothetical species | event candidate | ambiguous assignment | excluded hypothesis Prevents inferred candidates and theoretical proposals from being treated as confirmed observations.
Also called
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 17 findings · 27 questions.
Particle identity and composition Establishes what kind of particle is represented and separates species identity from a particular observation.
Subatomic classification depends on composition and physical identity, while observations often support several candidate assignments.
Species and occurrence
Distinguishes a particle kind from a prepared state or detection candidate.
Identity level
Record whether the subject is a species, a preparation or an event-level candidate, together with any unresolved identification.
- Does this record describe a particle species, a prepared quantum state or a candidate inferred from one event? definition
- Which observations distinguish the proposed species from other particles that could produce the same signature? boundary
Constituent structure
Represents elementary status, composite structure and links to constituent species.
Composition evidence
Record constituent descriptions or limits on resolved structure, including the framework and probed scale.
- Is this particle treated as elementary or composite, and within which physical framework? definition
- Which measurements establish constituent structure or constrain departures from pointlike behaviour, and at what scale? provenance
Intrinsic properties and symmetries Captures the properties used to distinguish species and constrain their physical behaviour.
Mass, spin, charges and conjugation relationships determine which particle assignments and processes are plausible.
Mass, spin and charge
Records intrinsic property assignments with their definitions and evidential limits.
Intrinsic property assignment
Keep mass, spin and electric charge distinct from energy, orbital angular momentum and other state-dependent quantities.
- What mass, spin and electric-charge values or limits apply, with which units, conventions and uncertainties? measurement
- Which assignments are directly constrained by experiment, and which depend on a theoretical interpretation? provenance
Quantum numbers and conjugation
Describes additional symmetry labels and the relationship to an antiparticle.
Symmetry labels
Attach quantum numbers and antiparticle claims to explicit conventions and applicable interaction regimes.
- Which additional quantum numbers distinguish this species, and under which interactions are they conserved or violated? definition
- Is the antiparticle distinct, identical to the particle or unresolved, and what evidence supports that assignment? provenance
Quantum state and kinematics Represents the preparation-dependent information needed to predict motion and measurement outcomes.
A species label alone cannot specify momentum, polarization, coherence or correlations with other particles.
Motion and reference frame
Makes energy and momentum meaningful through explicit frames, uncertainties and reconstruction assumptions.
Kinematic state
Record measured or inferred four-momentum without confusing total energy with rest mass.
- What energy and momentum are assigned, in which reference frame and with what correlated uncertainties? measurement
- Which components were measured directly and which were inferred using a mass hypothesis or event constraints? provenance
State preparation and correlations
Captures spin preparation, mixtures, superpositions and correlations relevant to the intended measurement.
Prepared quantum state
Record the state basis, preparation procedure and whether an independent single-particle description is adequate.
- Which polarization, helicity or other quantum-state information is established by the preparation, and in what basis? measurement
- Must entanglement, mixing or environmental coupling be represented to predict the proposed measurement? boundary
Interactions, production and decay Describes how the particle can be produced, interact and transform under specified conditions.
An agent must distinguish a channel that is permitted from one that is probable or experimentally accessible.
Production and scattering
Connects interaction channels to initial states, energy thresholds and measured probabilities.
Reaction feasibility
Evaluate production and scattering using the specified participants, kinematics and applicable selection rules.
- Which initial particles, target conditions and collision energies permit the proposed reaction? action
- What cross-section measurements or calculations apply at those energies, with which uncertainties and assumptions? measurement
Lifetime and decay channels
Represents stability claims, decay rates and observable daughter-particle channels.
Decay behaviour
Qualify stability by evidence and distinguish proper lifetime, observed flight time and channel branching fractions.
- What proper lifetime, decay width or lifetime bound is supported, and under what environmental conditions? measurement
- Which decay channels and branching fractions are established, and which final-state particles may escape detection? measurement
Observation and physical access Connects particle hypotheses to detector evidence and determines feasible physical operations.
Particles are often identified indirectly, and applicable manipulations depend on charge, lifetime, binding and preparation.
Signatures and inference
Separates detector observables from the hypotheses used to interpret them.
Identification evidence
Link tracks, deposited energy, timing, decay topology or missing momentum to candidate assignments and alternatives.
- Which detector observables support this identification, and which calibration or reconstruction assumptions enter? provenance
- What alternative particles or backgrounds remain compatible with the observations? boundary
Transport, confinement and measurement
Determines which operations are meaningful for the particle in its actual physical context.
Accessible operations
Condition proposed manipulation on the particle's interactions, lifetime and availability as an isolated or bound constituent.
- Can this particle exist as an isolated detectable state in the stated conditions, or must access proceed through a bound system or reaction products? boundary
- Which deflection, transport, trapping or measurement operations are feasible given its charge, lifetime, energy and coupling to the apparatus? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
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.
- "Subatomic" is a conventional scope term, not a strict diameter threshold; elementary particles have no established finite size.
- The listed kinds cover familiar Standard Model particles and hadrons but are not exhaustive of composite systems.
- Values are recalled approximations, not researched measurements; precision work should verify current Particle Data Group values, particularly neutron lifetime.
- Which of these check these first hold for the sense of subatomic particle this model covers, and on what evidence? provenance
Kinds and varieties
Recalled without web access and unsourced; every item is a lead to verify.
- Quarks
- Leptons
- Gauge bosons
- Higgs boson
- Baryons
- Mesons
- Which of these kinds and varieties hold for the sense of subatomic particle this model covers, and on what evidence? provenance
Identifiers and schemes
Recalled without web access and unsourced; every item is a lead to verify.
- Particle Data Group Monte Carlo particle numbering scheme - Electron: 11; photon: 22; proton: 2212; neutron: 2112 - Integer codes identify particle species for simulation and data exchange; many antiparticles use the negative of the corresponding particle code.
- Which of these identifiers and schemes hold for the sense of subatomic particle this model covers, and on what evidence? provenance
Real-world use
Recalled without web access and unsourced; every item is a lead to verify.
- Electron beams in microscopy, lithography and materials processing
- Proton beams in cancer radiotherapy
- Neutrons in materials analysis and nuclear reactors
- Positron annihilation in positron emission tomography
- Particle collisions and scattering in fundamental physics research
- Which of these real-world use hold for the sense of subatomic particle this model covers, and on what evidence? provenance
Typical measurements
Recalled without web access and unsourced; every item is a lead to verify.
- Rest mass - Species-dependent: photon 0; electron approximately 0.511; proton approximately 938.27 - MeV/c²
- Electric charge - Quarks: +2/3 or −1/3; electron: −1; proton: +1; neutron and photon: 0; antiparticles have opposite charge - elementary charge e
- Spin quantum number - Examples: electron, quarks, proton and neutron 1/2; photon 1; Higgs boson 0 - dimensionless
- Mean lifetime - Ranges from extremely short-lived resonances to particles with no observed decay; free neutron approximately 880 - s
- Which of these typical measurements hold for the sense of subatomic particle 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.
- Sufficiently energetic particle radiation can ionize matter, damaging living tissue and electronic components.
- Neutrons and sufficiently energetic particle beams can activate materials, producing radioactive nuclides.
- Particle beams can generate secondary radiation and deposit enough energy to damage equipment.
- Decay and annihilation can produce penetrating radiation; these are physical processes rather than equipment failure modes.
- Which of these failure modes and hazards hold for the sense of subatomic particle 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.
- Elementary particle - Has no established internal constituent structure; subatomic particles also include composite objects such as protons.
- Atom - An atom comprises a nucleus and bound electrons; subatomic particles include its constituents and other particle species.
- Atomic nucleus - A nucleus is a bound nuclear system of protons and neutrons, with ordinary hydrogen having a single proton; it overlaps with the broader category of composite subatomic objects.
- Quasiparticle - A quasiparticle is an effective excitation within a material or many-body system, rather than an independently existing vacuum particle species.
- Radiation - Radiation describes energy propagation or emission; a particle species can participate in radiation without being synonymous with it.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of subatomic particle this model covers, and on what evidence? provenance
What the second pass must settle
- Does the registry intend this entry to include entire atomic nuclei and exotic few-body bound systems, or should those be owned by neighbouring models?
- Which existing Vercy models already own elementary particles, composite particles, bosons or specific species, and which properties should be inherited through links?
- How should flavour states, mass eigenstates and oscillating neutral systems be represented without conflating species identity with state preparation?
- What evidence and terminology should distinguish established particles, resonances, hypothetical particles and virtual contributions to calculations?
- Which authoritative property compilations and primary measurements should supply values, uncertainties and revision provenance for the researched model?