1. Introduction Flashcards
Briefly describe the gravitational force
Acts between masses
- Responsible for the structure of the universe
- Obeys the inverse square law
Briefly describe the electromagnetic force
Acts bewteen charged particles
- Responsible for chemistry and EM waves
Briefly describe the weak force
Acts between particles with a “weak” charge
- Responsible for radioactive decay
Briefly describe the strong force
Acts between particles with a “colour” charge
- Holds the atomic nucleus together
What are the two main branches of fermions?
Leptons
Quarks
Which force do leptons feel, and what type of charge do they have?
Feel the weak force and the charged ones feel the EM
- Only weak charge, no colour charge
How many leptons are there and briefly describe them
Six - 3 that carry weak charge (electron, muon, tau)
3 of their neutrinos that carry no charge
What is the spin of a fermion?
h bar / 2
Which fermions are free?
Leptons, but not quarks
Why are quarks not free?
Confined to hadrons
Which forces do quarks feel?
All of them
What are hadrons?
Bound states of quark combinations
Briefly describe the two types of hadrons
Mesons - quark anti quark pair. Integer spin (boson) and integer charge
Baryons - qqq, 1/2 integer spin (fermion), integer charge
How do we describe particles interacting?
They decay/scatter via the exchange of GAUGE BOSONS
How are the range of the force and the mass related?
Range of force is inversely proportional to the boson mass
- Heavy boson -> short range -> slower interaction
