TR3.5

2021-09-27 Mon 12:00

Table of Contents

title: Zachary Second Reading Notes
author: Zachary Sayyah
course: PHYS201
source: KBhPHYS201QuantumWorldBookNotesIndex

1 Meet the Leptons

  • There are three families of subatomic particles
    • Flavor 1: the electron and it's nuetrino
    • Flavor 2: the Muon and it's nuetrino
    • Flavor 3: the the tau lepton and it's nuetrino
  • Leptons carry one-half unit of spin and are either neutral or have 1 negative charge
  • For every lepton there's an anti-lepton with an opposite unit of charge and the same mass
  • Leptons have no known size and in all theories describing them are point particles

1.1 Particles

  • Leptons are fundemental spin one half particles that experience no strong interactions and contain no quarks
  • Baryons are strong interacting particles that do contain quarks and have spin one half, but also 3/2 and 5/2 in some cases and are relatively heavy
  • Mesons are composite strongly interacting particles also made of quarks that have spin either 0 or 1.
  • Quarks are the fundamentally strongly interacting particles that are constituents of Baryons and have baryonic charge giving them a charge of 0 if two of them are united and 1 if 3 of them are
  • Force carriers are particles whose creation, annihilation, and exchange create forces. It is these particles that we believe have no substructure

1.2 Electrons

  • Electrons are Leptons
  • Has an opposite which is the positron
  • Effectively launched particle physics as we know it
  • Is beta radiation
  • Equations to bridge relativity and quantum mechanics in order to describe the electron predicted 1/2 spin and also anti-matter
    • Some particles are their own anti-particles

1.2.1 Radioactivity

  • They realized that helium nucleus's shouldn't be able to escape the nucleus of a particle and that it would have to escape through quantum tunneling
  • Gamma radiation is produced by a change in quantum state of the protons
  • Neutrino was suggested as a way to solve some of beta decay's issues
    • So was neutron
  • There are 3 types of neutrinos known
  • We detected Nuetrinos through weak interactions with things around them

1.3 Muons

  • Cosmic radiation kept giving rise to the theory that there were charged particles around 200x more massive than an electron
  • Muons appeared exactly like electrons but more massive
    • For some reason however it doesn't decay into an electron and like a gamma ray so we can assume it is somehow fundamentally different
      • This brings us back to it being a different flavor

1.4 ### The Muon Neutrino