Chapter 2 - Quarks and leptons Flashcards
What is a hadron?
A particle or antiparticle that can interact through the strong interaction and rest of the 4 fundamental interactions. A particle that consists of quarks or antiquarks.
What are baryons?
What are examples of baryons?
Hadrons that decay into protons.
Baryons consist of 3 quarks.
Antibaryons consist of 3 antiquarks.
Protons and neutrons.
What are mesons?
Hadrons that do not decay into protons.
They consist of a quark-antiquark pair.
Kaons and Pions.
Rest energy of products =
Total energy before collision − Kinetic energy of products
What are leptons?
Fundamental particles and antiparticles that do not interact through the strong interaction.
- Electron
- Muon
- Electron neutrino
- Muon neutrino
and respective antiparticles.
What are the lepton numbers?
Lepton +1
Antilepton -1
Non-lepton 0
What is the charge of the up, down and strange quarks?
u = +2/3
d = -1/3
s = -1/3
Antiquarks have opposite charges.
What are the two types of neutrino?
Electron neutrino
Muon neutrino
What is special about the Σ (sigma) and kaon particle?
They contain a strange or anti-strange quark.
What is the baryon number of every quark?
+1/3
What is the strangeness of a strange particle?
-1
What is the only stable baryon into which other baryons eventually decay?
Proton
What particles decay into pions?
Kaons
What particle decays into an electron?
Muon
What are strange particles?
Particles that are produced through the strong interaction and decay through the weak interaction.
They are always produced in pairs to conserve strangeness.
What is the quark combination of a proton?
uud
What is the quark combination of a neutron?
udd
What is the strangeness of the up, down and strange quarks?
u = 0
d = 0
s = -1
What is the exchange particle of the strong nuclear force?
Pion
What are the baryon numbers?
Baryon +1
Anti-baryon -1
Non-baryon 0
What quantities must be conserved in particle interactions?
Energy
Momentum
Charge
Lepton number
Baryon number
Strangeness (in a strong interaction only)
What is the role of an exchange particle?
An exchange particle carries the force from one particle to another.
Exchange particles produce the effects of attraction and repulsion.
Does strangeness need to be conserved in weak interactions?
No, strangeness must only be conserved in strong interactions.
Strangeness can change by 0, +1, or -1 in weak interactions.
SPECIFICATION REQUIRES:
Appreciation that particle physics relies on the collaborative efforts of large teams of scientists and engineers to validate new knowledge.
SPECIFICATION REQUIRES:
Appreciation that particle physics relies on the collaborative efforts of large teams of scientists and engineers to validate new knowledge.
Muons and electrons have different lepton numbers!
They both have to be conserved in particle interactions.
Muons and electrons have different lepton numbers!
They both have to be conserved in particle interactions.
Quark changes occur due to the…
Quark changes occur due to the weak interaction.
