Chapter 7: A-tom!

This is quite a large chapter, it goes through in a lot of detail, the Standard Model, which outlines all elementary particles that make up EVERYTHING and the forces that are at work amongst them. The major theory behind this is Quantum Electrodynamics.

The best way to organize the information in this chapter in a chart:

MATTER
Quarks àare found within things like protons(made up of uud combo) , and the properties that we have attributed to those larger particles is actually a result of the sum of what the quarks are doing inside them.
u à up	charge +2/3
d à down	charge -2/3
c à charm	high mass, but long lifetime
s à strange	charge -2/3
b à bottom	last one discovered, pairs with theoretical top quark
t ? à top	hypothesized, but not found yet
Leptons
Ve à electron neutrino	no charge, almost no mass, this one is associated in reactions with electrons
e à electron	a lot of charge in a very small mass, according to calculations it should be infinitely heavy, but its not
Vµ àmuon neutrino	no charge and almost no mass, discovered and named by Fermi. This variaton of nutrino is associated with muon reactons
µ à muon	cousin of electron, but much heavier, which changes its radius and energy level.
Vτ à	never been pinned down experimentally, only theoretically, but its existance is widely accepted
τ	cousin of electron, but much heavier
Forces (messenger particles)
electromagnetism	forces associated with -ve or +ve charge, and magnets, effects can be observed in everyday life
weak force	between quarks, responsible for radioactivity and nuclear decay.
Strong force	the force that hold the nucleus together, in the form of the particles called Gluons. A lot of properties of compound atoms are the result of the strong force “leaking out” of the nucleus.

Parity Violation is the reason that we are here today. If the theory of parity held true, after the Big Bang there would have been an equel amount of matter and antimatter, which would have canceled each other out, leaving too low an energy level for anything to happen. Luckily, there was a bit more matter than antimatter, so when things started annihilating, there was enough matter (and energy) for everything as we know it to form.

An interesting rule that I came across in this chapter is the Totalitarian Rule of Physics “Anything that isn’t forbidden is compulsory.” This means that if something cannot be completely ruled out it has to be happening. With these elementary particles, and the forces acting on them, whether or not a specific action is occurring is a yes/no answer, no grey area.

Quarks are peculiar because the closer they are to each other, the weaker the forces between them are (that is the weak force). So if quarks are separated, the larger the distance, the more energy needed to over come the Weak force. This means that there an be no such thing as a free Quark, they are always with other particles with forces acting on them. The also have “asymptotic freedom” which means that they will get closer and closer but never actually touch. This is counter intuitive and opposite to electromagnetism which most people are more familiar with.