Particle Physics Flashcards
What are the two main types of fundamental particles?
quarks and leptons
What are the two families of hadrons
Baryons and Mesons
What are hadrons?
Particles made of quarks, including baryons (3 quarks) and mesons (quark-antiquark pairs).
Name two baryons.
Proton and neutron.
Name two mesons.
Pion (π) and kaon (K).
What are leptons?
Fundamental particles that do not experience the strong nuclear force, e.g., electrons, neutrinos, and muons.
What is the quark structure of a proton?
uud (up-up-down).
What is the quark structure of a neutron?
udd (up-down-down).
What are the four fundamental forces?
Strong nuclear, electromagnetic, weak nuclear, gravity.
Which force acts between quarks?
Strong nuclear force, mediated by gluons.
What is the exchange particle of the electromagnetic force?
virtual Photon (γ).
What is the exchange particle of the weak force?
W+, W- bosons.
Which force is responsible for beta decay?
Weak nuclear force.
Which force has an infinite range?
Electromagnetic and gravity (strong and weak forces have short ranges).
What are the four key conservation laws in particle interactions?
Charge, baryon number, energy-momentum.
Is strangeness always conserved?
No, it is conserved in strong interactions but not in weak interactions.
What is the baryon number of a proton?
+1.
What is the baryon number of a neutron?
+1.
What is the baryon number of an electron?
0 (only hadrons have a baryon number).
What is the lepton number of an electron?
+1.
What is the lepton number of an electron neutrino?
+1.
What is the lepton number of a muon?
+1, but in the muon lepton family.
What happens in beta-minus decay?
A neutron turns into a proton, emitting an electron and an electron antineutrino.
Write the equation for beta-minus decay.
n → p + e⁻ + ν̅ₑ
What is the exchange particle in beta-minus decay?
W⁻ boson.
What happens in beta-plus decay?
A proton turns into a neutron, emitting a positron and an electron neutrino.
Write the equation for beta-plus decay.
p → n + e⁺ + νₑ
What is the exchange particle in beta-plus decay?
W⁺ boson.
What happens in electron capture?
A proton absorbs an electron to become a neutron, emitting an electron neutrino.
What happens in electron-positron annihilation?
An electron and positron collide, annihilating into two photons.
What happens in pair production?
A high-energy photon creates an electron and positron pair.
What are strange particles?
Particles that contain a strange quark, such as kaons (K⁺, K⁻, K⁰).
How are strange particles produced?
Through the strong interaction, so strangeness is conserved in production.
How do strange particles decay?
Via the weak interaction, so strangeness is not conserved in decay.
What is the charge and strangeness of a K⁺ meson?
Charge = +1, Strangeness = +1.
What is the charge and strangeness of a K⁰ meson?
Charge = 0, Strangeness = +1.
