strong interaction

Strong contribution boundary

Record whether the claim concerns binding, a transition, scattering or a medium response, including possible mixed contributions.

1. Which specific contribution or observable is attributed to the strong interaction? definition
2. Could electromagnetic or weak dynamics produce the same observed final state, and how are their contributions distinguished? boundary

Colour and effective participants

Record colour representations in a microscopic description or hadronic participants in an effective description.

1. Are the resolved participants quarks and gluons, or colour-singlet hadrons described through effective interactions? definition
2. What calculation or evidence supports connecting the chosen effective interaction to strong dynamics? provenance

Running coupling context

Require scales and conventions alongside any recorded strong coupling. [CMS coupling measurement](https://cmsexperiment.web.cern.ch/news/quarks-running-freedom-probing-strong-force-high-precision)

1. What physical momentum scale characterises the observable, and how were renormalisation and any factorisation scales chosen? measurement
2. Which scheme, active-flavour prescription and uncertainty accompany the quoted alpha_s? provenance

Controlled description

Record why perturbative QCD, lattice QCD, an effective theory or a phenomenological treatment is suitable for this observable.

1. What expansion, numerical limit or empirical validation supports this method in the specified regime? boundary
2. Which missing inputs or uncontrolled corrections require changing the method or withholding a prediction? action

Hadronisation dependence

Record how a partonic prediction is translated into hadron-level evidence and what uncertainty that translation introduces. [CERN partons to hadrons](https://home.cern/partons-hadrons/)

1. Which hadrons or jet observables support the inferred quark or gluon dynamics? measurement
2. Which fragmentation inputs or hadronisation assumptions affect the inference, and where were they validated? provenance

Deconfinement evidence

Record medium conditions and converging observables supporting a deconfinement interpretation, including jet modification where relevant. [CERN heavy ions and quark-gluon plasma](https://home.cern/science/physics/heavy-ions-and-quark-gluon-plasma/)

1. Which temperature, density or energy-density estimates apply, and how were they inferred? measurement
2. Which observations support deconfined matter, and which competing explanations remain viable? boundary

Strong channel admissibility

Record thresholds and relevant conservation constraints, distinguishing net flavour changes from quark-antiquark pair production.

1. Do the proposed initial and final states satisfy energy-momentum, angular-momentum, charge and net-flavour constraints for a strong process? boundary
2. If a channel is allowed, what additional matrix-element or empirical information is needed before estimating its rate? action

Residual interaction description

Record the hadronic channel, effective interaction and range of validity needed to interpret binding or scattering.

1. Which hadrons, spin and isospin channel, and momentum or separation range define the residual interaction being modelled? definition
2. Which phase shifts or binding observables constrain the description, and are additional many-body terms needed? measurement

Measurement comparability

Record collision or bound-state conditions, observable definitions and corrections that determine comparability.

1. What beam species, energy, kinematic cuts, channel and observable definition apply, including the jet algorithm where relevant? measurement
2. Which dataset or calculation supplies the result, and what detector, background or unfolding corrections were applied? provenance

Prediction readiness

Assess whether uncertainties and alternative descriptions permit the intended use of a strong-interaction prediction.

1. Do experimental and theoretical uncertainties, including relevant correlations, support the proposed interpretation or distinguish competing descriptions? measurement
2. Should the agent proceed with the calculation, request a discriminating observable, or leave the mechanism unresolved? action

Kinds and varieties

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• Fundamental colour force (gluon-mediated QCD between quarks and gluons)
• Residual strong force / nuclear force (meson-mediated nucleon-nucleon interaction)
• Perturbative QCD / asymptotically free high-Q² regime
• Non-perturbative confining regime (flux tubes, hadronization)
• One-pion-exchange long-range nuclear attraction
• Short-range repulsive nucleon core
• Deconfined quark-gluon plasma
• Three-nucleon and other multi-body residual forces

1. Which of these kinds and varieties hold for the sense of strong interaction this model covers, and on what evidence? provenance

Identifiers and schemes

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• Wikidata - Q11415 - Item for the strong interaction as a fundamental force.
• GND - 4182921-9 - German National Library subject heading.
• LCSH - sh98005979 - Library of Congress subject heading.
• BnF - cb119927693 - Bibliothèque nationale de France authority.
• Standard Model gauge factor - SU(3)_c - Colour gauge group of QCD; the theory, not a catalogue number.
• PDG constant - αs(mZ) - Conventional reference value of the strong coupling at the Z mass.

1. Which of these identifiers and schemes hold for the sense of strong interaction this model covers, and on what evidence? provenance

Standards and regulation

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• Review of Particle Physics, Quantum Chromodynamics chapter - Particle Data Group (LBNL; published with APS/IOP)
• CODATA recommended values of the fundamental physical constants (includes αs) - Committee on Data of the International Science Council / NIST
• FLAG reviews of lattice-QCD determinations of αs - Flavour Lattice Averaging Group
• ISO 80000-10 (quantities and units in atomic and nuclear physics) - International Organization for Standardization

1. Which of these standards and regulation hold for the sense of strong interaction this model covers, and on what evidence? provenance

Real-world use

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• Binds protons and neutrons in every nucleus heavier than ¹H, setting nuclear stability, magic numbers and the chart of nuclides.
• Supplies most of the visible mass of ordinary matter: QCD field energy, not quark rest masses, accounts for about 99% of the proton and neutron mass.
• Powers stellar fusion and, through residual binding-energy differences, nuclear fission reactors and fission/fusion weapons.
• Governs hadron-collider observables: jet production, parton showers, hadronization and PDF fits at the LHC and elsewhere.
• Is the dynamics under study in heavy-ion programmes (RHIC, LHC-ALICE) that form a quark-gluon plasma, and in lattice-QCD calculations of the hadron spectrum and nucleon-nucleon potentials.

1. Which of these real-world use hold for the sense of strong interaction this model covers, and on what evidence? provenance

Typical measurements

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• Strong coupling αs(mZ²) in the MS-bar scheme (Nf = 5) - 0.1180 ± 0.0009 (PDG 2025 average) - 1 (dimensionless)
• Range of the colour (gluon) force inside a hadron - ≲ 0.8 - fm
• Range of the residual nucleon-nucleon force - about 1-3 - fm
• Strength relative to electromagnetism at ~1 fm - about 100 - 1 (ratio)
• QCD string tension / confining force scale - about 1 GeV/fm, or order 10^4 N in older popular estimates - GeV/fm
• QCD scale ΛQCD - about 200-350 - MeV
• Average nuclear binding energy per nucleon (medium/heavy nuclei) - about 7-9 (peak near 8.8 around 56Fe) - MeV

1. Which of these typical measurements hold for the sense of strong interaction this model covers, and on what evidence? provenance

Failure modes and hazards

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• Colour confinement: isolated quarks are not observed; energy spent separating them creates new quark-antiquark pairs and hadron jets rather than free partons.
• The residual attraction falls roughly exponentially while proton Coulomb repulsion falls as 1/r, so nuclei with Z > 82 become increasingly unstable against fission and α decay.
• A short-range repulsive core prevents nuclear collapse but also limits how tightly nucleons can bind.
• Release of residual binding energy in an uncontrolled chain reaction or explosive assembly (criticality accidents, nuclear weapons).
• Perturbative QCD fails in the infrared (coupling of order one below ~1 GeV), so low-energy predictions must use lattice QCD, chiral EFT or models.
• The QCD θ term would generate a large neutron electric dipole moment that is not seen (the strong-CP problem).

1. Which of these failure modes and hazards hold for the sense of strong interaction this model covers, and on what evidence? provenance

Regional variation

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• In contemporary particle physics, "strong interaction" or "strong force" means QCD; "nuclear force" or "residual strong force" means the internucleon potential.
• Older literature and much nuclear-engineering usage still call the internucleon potential the "strong nuclear force".
• German distinguishes starke Wechselwirkung (QCD) from Kernkraft / Nukleon-Nukleon-Wechselwirkung (residual).
• Japanese uses 強い相互作用 for the fundamental interaction and 核力 for the residual nuclear force.
• French: interaction forte versus force nucléaire; Russian: сильное взаимодействие versus ядерные силы.

1. Which of these regional variation hold for the sense of strong interaction this model covers, and on what evidence? provenance

Neighbouring kinds and how to tell them apart

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• Weak interaction - Flavour-changing SU(2)L force mediated by massive W±/Z; range ~10⁻¹⁸ m; leptons participate. Test: neutrinos and flavour-changing decays versus colour-charged jets and nuclear binding, which the weak force does not provide.
• Electromagnetism - U(1)em force mediated by the photon, long-range 1/r², acts on electric charge. Test: leptons feel it and colour-neutral atoms bind chemically; they do not form hadrons or nuclear bound states by electromagnetism alone.
• Gravitation - Universal spacetime curvature, ~10³⁸ times weaker than the strong force at 1 fm. Test: negligible in laboratory nuclear and particle processes; dominates only at macroscopic mass.
• Nuclear force (residual strong force) - Effective interaction between colour-singlet hadrons, meson-mediated, range 1-3 fm. Test: acts on nucleons, not free colour; Yukawa falloff and a repulsive core, versus a non-diminishing colour flux tube inside a hadron.
• Electroweak interaction - Unified SU(2)×U(1) description of EM and weak forces above ~100 GeV. Test: W/Z and photon versus eight coloured gluons; grand unification with QCD remains unestablished.
• Yukawa meson-exchange interaction - Effective field description of the residual nucleon force, not the fundamental colour force. Test: pion mass sets the longest range; it does not describe gluon self-coupling, jets or the quark-gluon plasma.

1. Which of these neighbouring kinds and how to tell them apart hold for the sense of strong interaction this model covers, and on what evidence? provenance