Elementary Particles

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• Elementary Particles

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1. The Big Question of Particle Physics
How did we get from here to here?
And what does it have to do with heavy
quarks?
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Time
Seems like
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• Just after the Big Bang
• symmetric Universe
• equal number of particles and antiparticles
• Now
• asymmetric Universe
• planets, stars, galaxies, Wayne State,

Note macroscopic laws of Nature do not
distinguish matter and antimatter
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A 10,000,000.00 Swedish Kronor questionWhere
did all the antimatter go?

• The Onion paradigm
• identify degrees of freedom
• see if the problem has a solution
• if not, dig deeper

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What are the right degrees of freedom?

• Fire
• Water
• Earth
• Air
• that is, according
• to the Greeks!

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What would be the modern picture?
Imagine that we have a very powerful microscope
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Modern understanding the onion picture
Atom
Lets see whats inside!
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Modern understanding the onion picture
Nucleus
Lets see whats inside!
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Modern understanding the onion picture
Protons and neutrons
Lets see whats inside!
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Modern understanding the onion picture
Collective name for particles containing 3 quarks
Mesons and baryons
Collective name for particles containing quark
and antiquark
Lets see whats inside!
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Modern understanding the onion picture
Collective name for particles containing 3 quarks
(such as proton and neutron)
Mesons and baryons
Collective name for particles containing quark
and antiquark
Lets see whats inside!
Note apparent excess of matter over antimatter
can be traced to excess of the number of baryons
over antibaryons. Thus our Big Problem is called
Problem of Baryon Asymmetry of the Universe.
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Modern understanding the onion picture
Quarks and gluons
Lets see whats inside!
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Modern understanding the onion picture
?
so the answer depends on the energy scale!
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same thing about the interactions
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Unification of forces
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The Standard Model of particle physics
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The Standard Model of Elementary Particle Physics

• Periodic table of matter
• Interactions electromagnetic, weak, strong,
  (gravity)
• Contains 26 parameters needs experimental
  input

Higgs particle
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Conditions for baryon asymmetry
Matter-antimatter imbalance in the Universe
A.D. Sakharov

• Baryon (and lepton) number - violating processes
• to generate asymmetry
• Universe that evolves out of thermal equilibrium
• to keep asymmetry from being
  washed out
• Matter interactions differ from antimatter
  interactions (Microscopic CP-violation)
• to keep asymmetry from being
  compensated in the anti-world

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Can Standard Model explain baryon asymmetry?

• does it have the right stuff?
• what are the conditions for the baryon
  asymmetry?
• does it have enough of the right stuff?

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Experimental methods
video
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Experimental methods
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Experimental Facilities I
Cornell University
SLAC
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Experimental Facilities II
KEK (Japan)
Fermilab (Batavia, IL)
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What do physics PhDs do?

• Science route
• Research in physics (national lab, research
  university)
• Teaching and research (college)
• Industry route
• Computing/engineering jobs in companies
• Finance industry (problem solving)
• Scientific Publishing route