Chapter 2 - Quarks and Leptons Flashcards
What is a cosmic ray?
High energy particles that travel through space from the stars
What are the two groups that all matter are divided into?
Hadrons and leptons
Describe some features of hadrons
- interact through all four fundamental forces
- interact through the strong and electromagnetic forces if charged
- apart from the proton (which is stable) they decay through the weak force
THEY DO INTERACT THROUGH THE STRONG FORCE
Describe some features of leptons
-interact through the weak force, gravitational force and the electromagnetic force
THEY DO NOT INTERACT THROUGH THE STRONG FORCE
What two groups can hadrons be divided into?
Baryons and mesons
What are baryons?
Protons and all other hadrons that decay into protons, directly or indirectly
What are mesons?
Hadrons that do NOT include protons in their decay products
What are quarks?
Quarks are the smaller particles that make up baryons and mesons
What does fundamental mean?
They can’t be broken down any further
What must be conserved in ANY reaction?
Charge, energy
Strange particles are all decayed by which force?
Weak force
In which interaction is strangeness always conserved? (Weak/strong)
Strong
What do mesons consist of?
A quark and an antiquark
What do baryons consist of?
Three quarks - but the charge must add to make a whole number (for example a proton is uud(2/3 + 2/3 +-1/3 =1))
What must be conserved in particle and antiparticle interactions and decays?
Energy, charge, lepton number, strangeness, baryon number
