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level: Conservation laws and particle interactions

Questions and Answers List

level questions: Conservation laws and particle interactions

QuestionAnswer
Gravity, electromagnetic, weak nuclear, and strong nuclear.Four Fundamental Forces
What are the four fundamental forces?Gravity, electromagnetic, weak nuclear, and strong nuclear.
Particles that carry energy and momentum between particles experiencing a force.Exchange Particles
What do exchange particles do?They carry energy and momentum between particles experiencing a force.
Think of repulsion as two people throwing a heavy ball, where the momentum pushes them apart.Example of Repulsion
How can repulsion be explained using exchange particles?It can be compared to throwing a heavy ball between two people, which transfers momentum and causes them to move apart.
Can be imagined with a boomerang, where the exchange particle curves back, pulling the two people closer.Example of Attraction
How can attraction be explained using exchange particles?It’s similar to the exchange of a boomerang, which brings the two people closer together.
A fundamental force with the exchange particle being the gluon. Its range is 3 × 10^-15 m, and it acts on hadrons.Strong Force
What is the exchange particle for the strong force, and what does it act on?The exchange particle is the gluon, and it acts on hadrons.
A fundamental force with the exchange particle being the W boson (W⁺ or W⁻). Its range is 10^-18 m, and it acts on all particles.Weak Force
What is the exchange particle for the weak force, and what particles does it act on?The exchange particle is the W boson (W⁺ or W⁻), and it acts on all particles.
A fundamental force with the exchange particle being the virtual photon (γ). Its range is infinite, and it acts on charged particles.Electromagnetic Force
What is the exchange particle for the electromagnetic force, and what does it act on?The exchange particle is the virtual photon (γ), and it acts on charged particles.
A fundamental force with the hypothesized exchange particle being the graviton (not on specification). Its range is infinite, and it acts on particles with mass.Gravity
What is the exchange particle for gravity, and what does it act on?The hypothesized exchange particle is the graviton, and it acts on particles with mass.
Responsible for processes such as beta decay, electron capture, and electron-proton collisions.Weak Nuclear Force
What is the weak nuclear force responsible for?It is responsible for beta decay, electron capture, and electron-proton collisions.
Electron capture a process where a proton and electron interact, resulting in a neutron and an electron neutrino.Electron Capture
What is the equation for electron capture?p + e⁻ → n + νₑ
Electron-proton collision is a process where a proton and electron interact, resulting in a neutron and an electron neutrino.Electron-Proton Collision
What is the equation for an electron-proton collision?p + e⁻ → n + νₑ
The equations for electron capture and an electron-proton collision are the same, but a different exchange particle is used.Comparison of Electron Capture and Electron-Proton Collision
How do the equations for electron capture and electron-proton collision compare?They are the same, but a different exchange particle is used in each process.
A process where a proton decays into a neutron, a positron, and an electron neutrino.Beta-Plus Decay
What is the equation for beta-plus decay?p → n + e⁺ + νₑ
A process where a neutron decays into a proton, an electron, and an electron antineutrino.Beta-Minus Decay
What is the equation for beta-minus decay?n → p + e⁻ + νₑ
These properties must always be conserved in particle interactions: Energy and momentum Charge Baryon number Electron lepton number Muon lepton numberApplications Of Conservation Laws
What properties must always be conserved in particle interactions?Energy and momentum, charge, baryon number, electron lepton number, and muon lepton number.
Strangeness must only be conserved during strong interactions.Strangeness In Strong Interactions
When must strangeness be conserved?Strangeness must only be conserved during strong interactions.
In beta-minus decay (a weak interaction), the conservation laws include charge, baryon number, and electron lepton number, but strangeness does not need to be conserved. The interaction is represented as: n → p + e⁻ + νₑConservation Laws In Beta-Minus Decay
What conservation laws apply in beta-minus decay?Charge, baryon number, and electron lepton number are conserved, but strangeness does not need to be conserved.
Before the interaction: Charge: 0 After the interaction: Charge: 1 - 1 + 0 = 0Charge Conservation In Beta-Minus Decay
How is charge conserved in beta-minus decay?Before the interaction, charge is 0. After the interaction, charge is 1 - 1 + 0 = 0, so charge is conserved.
Before the interaction: Baryon number: 1 After the interaction: Baryon number: 1 + 0 + 0 = 1Baryon Number Conservation In Beta-Minus Decay
How is baryon number conserved in beta-minus decay?Before the interaction, the baryon number is 1. After the interaction, the baryon number is still 1, so it is conserved.
Before the interaction: Electron lepton number: 0 After the interaction: Electron lepton number: 0 + 1 - 1 = 0Electron Lepton Number Conservation
How is the electron lepton number conserved in beta-minus decay?Before the interaction, the electron lepton number is 0. After the interaction, the electron lepton number is 0 + 1 - 1 = 0, so it is conserved.
Before the interaction: Muon lepton number: 0 After the interaction: Muon lepton number: 0 + 0 + 0 = 0Muon Lepton Number Conservation
How is the muon lepton number conserved in beta-minus decay?Before the interaction, the muon lepton number is 0. After the interaction, it remains 0, so it is conserved.
In beta-minus decay, strangeness does not need to be conserved because it is a weak interaction.Strangeness Conservation In Beta-Minus Decay
Is strangeness conserved in beta-minus decay?No, strangeness does not need to be conserved in beta-minus decay since it is a weak interaction.
Both beta-minus decay and beta-plus decay are caused by the weak interaction because there is a change in quark type.Beta-Minus And Beta-Plus Decay
What causes beta-minus and beta-plus decay?Beta-minus and beta-plus decay are caused by the weak interaction due to a change in quark type.
In beta-minus decay, for a neutron to change into a proton, a down quark changes into an up quark.Beta-Minus Decay Quark Change
What quark change occurs during beta-minus decay?A down quark changes into an up quark.
In beta-plus decay, for a proton to change into a neutron, an up quark changes into a down quark.Beta-Plus Decay Quark Change
What quark change occurs during beta-plus decay?An up quark changes into a down quark.
In Feynman diagrams, the y-axis represents time, and the x-axis represents space.Y-Axis and X-Axis Representation
What do the y-axis and x-axis represent in Feynman diagrams?The y-axis represents time and the x-axis represents space.
A vertex in Feynman diagrams is where particles and exchange particles meet. Vertices represent points of interaction (e.g., electromagnetic, weak, or strong forces).Vertex Definition
What does a vertex represent in a Feynman diagram?A vertex represents the point where particles and exchange particles interact.
Incoming particles enter the diagram at the bottom, while outgoing particles exit at the top.Incoming and Outgoing Particles
Where do incoming and outgoing particles appear in a Feynman diagram?Incoming particles enter at the bottom, and outgoing particles leave at the top.
Particles are represented by straight lines with arrows that indicate their direction forward in time.Particle Representation
How are particles represented in a Feynman diagram?Particles are represented by straight lines with arrows indicating their direction in time.
Exchange particles are represented by wavy lines without arrows. Their transfer generally occurs from left to right unless an arrow above the wavy line indicates otherwise.Exchange Particle Representation
How are exchange particles represented and directed in a Feynman diagram?Exchange particles are represented by wavy lines with no arrows, transferring from left to right unless otherwise indicated.
In Feynman diagrams, hadrons/quarks appear on the left side, and leptons on the right. These groups must never meet at a vertex.Hadrons and Leptons Separation
Where are hadrons and leptons positioned in a Feynman diagram, and can they meet at a vertex?Hadrons/quarks are on the left, and leptons are on the right, and they must not meet at a vertex.
In Feynman diagrams, charge, baryon number, and lepton number must be conserved at each vertex.Conservation at Vertices
What must be conserved at each vertex in a Feynman diagram?Charge, baryon number, and lepton number must be conserved at each vertex.
Lines in Feynman diagrams must not cross over each other.Line Rules in Feynman Diagrams
What rule applies to line crossings in Feynman diagrams?Lines must not cross over each other in Feynman diagrams.