Fundamental particles Flashcards
What is a fundamental particle?
It is a particle that it is made up of nothing it cannot be broken down.
What are the six quarks?
Up and Down, Top and Bottom, strange and charm.
What is Deep-inelastic scattering?
It involves firing electrons at protons at very high energies.
What are the four fundamental forces?
Weak, gravity, strong and electromagnetic.
What Are the exchange particles of each force?
Weak = W+, W-, Z0 Strong = gluon Electromagnetic = Photon Gravity = graviton
What are the nature of the fundamental forces?
Weak is responsible for radioactive decay
Strong acts between quarks
Electromagnetic acts between charge particles
gravity acts between particles with mass
What is the electromagnetic force?
It is the source of the contact forces between everyday objects. On the quantum scale the electromagnetic interaction occurs between charged particles most commonly electrons and protons. The photon acts over infinite distance however the strength decrease with an inverse-square relationship to the distance 1/r^2.
What is the strong nuclear force?
It is an extremely short ranged force typically on the scale of 10^-14 or 10^-15 and it acts between quarks. It has a very high magnitude 137 times larger than the electromagnetic force. It is the force that hold nucleons together.
What is the weak force?
The weak force is responsible for beta+ and beta- decay. It is a million times weaker than the string force and acts over a range of 10^-18 which is 0.1% of the diameter of a proton.
What are Feynman diagrams?
They are pictorial ways of representing the interactions of quantum particles.
What are the rues of Feynman diagrams?
- Particles are represented in straight lines with arrow heads
- Exchange particles are represented with wavy lines
- Time moves on the x-axis
- Particles are created and annihilated at the vertices between lines
- Particles made up of quarks have the quark lines drawn parallel and next to each other
- Exchange particles generally transfer from left to right unless indicated by an arrow above the wavy line.
What are leptons?
They do not ‘feel’ the strong force. Are subject to the weak force. they are fundamental particles.
Examples: electron, muon, tau…
What are hadrons?
They are made up of quarks and feel the strong force.
What are baryons?
They are made up of three quarks, anti-baryons are made up of three anti-quarks. e.g protons neutrons etc
What are mesons?
The are made up of a quark anti-quark pair.
e.g Pions-pi+ (ud’), Kaon-K+ (us’) plus antiparticles.
