Chapter 2 - Fundamental Particles [Complete] Flashcards
What is a hadron?
Anything that is made up of quarks
What is a meson?
A quark anti-quark pair, for example a pion (a combination of up and down - Pion+ is up, anti down)
What are the 6 laws of conservation in particle equations?
Conservation of baryon number, conservation of lepton number, conservation of charge, conservation of momentum, conservation of strangeness, and conservation of mass-energy
Do leptons experience the strong force, the weak force, or both?
The weak force only, as they do not have quarks which would interact with the strong force
Give 2 examples of leptons
Muon, electron, Tau, with their antiparticles and neutrinos
What is a muon?
A type of lepton with mass about 200x that of the electron which is unstable but has an unusually long lifetime. It decays into neutrinos and an electron/positron
What is weird about the conservation of strangeness?
It is conserved in strong interactions, but not in weak ones. This is as in weak interactions the strange quark would change flavour
What is a fundamental particle?
One of the base building blocks of the universe, as far as we know, they cannot be broken down into anything smaller
What is an antiparticle?
An antiparticle is a particle with the same mass-energy as its particle counterpart, but with an opposite charge. When a particle-antiparticle pair meets, they annihilate and convert to gamma ray photons
What two quarks combine together to make protons and neutrons, and how many are in each?
Up and down quarks combine in threes to formulate protons and neutrons
What is deep inelastic scattering?
When scientists fire two particles at very high speeds into each other in order to observe what happens and what they may be made up of. For example, when they fire an electron into a proton, the proton splits and explodes into numerous other particles due to the photon interactions between its quarks and the electron. The word inelastic here means that energy is lost
What are the four fundamental forces and their exchange particles?
Strong, weak, electromagnetic and gravity, with the exchange particles gluons, [W+, W-, Z0]s, photons, and gravitons respectively
What is the rule for the strength of a photon over distances?
It declines in accordance with the inverse square law, whereby if the distance increases by, for example, double, the force is divided by 4. This can be shown in the equation 1/r^2 x energy
Is the strong force stronger or weaker than the electromagnetic one, and if so, by what degree is it smaller or greater?
It is 137 times stronger
What does the strong force do?
Holds nucleons such as protons and neutrons together
