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The Big BAng and Classes of Particles

Kevin Zheng

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Big Bang

  • Georges Lemaitre - Belgian priest - the world began with a single primordial atom
  • The world started off in a high temperature, high density singularity
  • NOT AN EXPLOSION - just space expanding
  • Einstein’s General relativity, Hubble’s discovery of the movement of galaxies and discover of CMB

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10^-43 seconds

  • AKA Planck’s time/ Planck’s epoch
    • Before this time, all laws of physics break down
    • Impossible to trace time back and understand what exactly happened
  • Four fundamental forces are formed
  • Matter and Antimatter form

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Four Fundamental Forces

  • Gravity - matter attracts matter/ bends spacetime
  • Electromagnetism - Lorentz force, electricity and magnetism
  • Weak force - responsible for decay, exchange of W and Z bosons
  • Strong force - strongest fundamental force, holds quarks and gluons together to make protons, neutrons and etc.

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The rest Part 1 (approx. 10^28 Kelvin)

10^-35

Inflation:

Basically just rapid expansion of space

10^-33

-Inflation stops

-1 billion and 1 particles of matter for 1 billion particles of anti-matter creates the world

-Leptons and Quarks vs anti-leptons and anti-quarks

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The rest Part 2

0.0001 seconds

Hadrons, anything made of quarks form basically just protons - baryogenesis

Universe cools and continues to expand

100 seconds

Electrons and Positrons annihilate

Neutrons and Protons make deuterons which eventually make helium

Lots of photons

1 billion degrees

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The rest Part 3

  • Universe cools down
  • Protons and electrons bind to create neutral hydrogen and eventually come together with helium to create stars
  • In stars, fusion and then supernova spits matter everywhere
  • Matter forms galaxies, planets and etc.

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Classes of Particles

Fundamental

  • Leptons (conserved)
    • electron, muon, tauon, and respective neutrinos
  • Quarks
    • Top (truth), bottom (beauty), up, down, strange, charm
  • Gauge bosons
    • Carry nuclear force strong or weak
    • gluons

Composite

  • Hadrons
    • All particles made of quarks
    • Mesons - quark and antiquark
      • tetraquarks
    • Baryons - made of 3 quarks
      • Protons and neutrons

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Classes continued

Fermions

  • Half integral spin
    • ½ for electrons
  • Enrico Fermi
  • Subject to Pauli Exclusion

Bosons

  • Integral spin
    • 1 for photons
  • Satyendra Nath Bose
  • Prefer the same quantum state

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Final Stuff

  • 4 fundamental forces - gravity, weak and strong, and electromagnetism
  • Leptons and quarks are fundamental particles
  • Gauge boson aka Gluons
  • Baryogenesis
  • Fermions and Bosons

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