Introduction%20to%20Particle%20Physics

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Introduction to Particle Physics

• How to compute the Universe?

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What do we study?
How did we get from here to here?
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So, how did we get from particles to galaxies?
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Brief history of the Universe
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Thus, we have to understand what our world is
made of
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What is the world made of?

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

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Modern understanding the onion picture
Nucleus
Lets see whats inside!
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Modern understanding the onion picture
Lets see whats inside!
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Modern understanding the onion picture
Mesons and baryons
Lets see whats inside!
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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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Aside units used in particle physics
Energy electron-volt 1 eV 1.6x10-19
J (energy that an electron gains going through
a potential difference of 1 Volt)
E mc2, so set c1! natural
units Mass electron-volt
proton mass mp 938.27 MeV Momentum electron-vo
lt
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same thing about the interactions

• The answer depends on the energy scale.

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Unification of forces
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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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Open questions

• Higgs particle is not (yet) discovered
• mechanism of electroweak symmetry breaking
• Standard Model does not have enough asymmetry
  between particles and antiparticles to create the
  Universe as we know it
• CP-violation and baryonogenesis
• New Physics beyond the Standard Model?
• supersymmetry, strings, extra dimensions

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Example What is CP(T)?
Classical mechanics is invariant under C,P, and T!
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Classical Field Theory EM
Maxwells equations are invariant
under C,P, and T!
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Why do we want to study CP-violation?
Matter-antimatter imbalance in the Universe

• Baryon (and lepton) number - violating processes
• to generate asymmetry
• Universe that evolves out of thermal equilibrium
• to keep asymmetry from being
  washed out
• Microscopic CP-violation
• to keep asymmetry from being
  washed out

A.D. Sakharov
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How to observe CP-violation?

• I. Intrinsic particle properties
• electric dipole moments

Low energy strong interaction effects might
complicate predictions!
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II. Transitional particle properties
Low energy strong interaction effects complicate
predictions!
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Why study B-physics?
B-factories are hunting for signs of
CP-violation in the decays of
B-mesons

• Possibility to control strong interactions
• controllable theoretical expansions
• New Physics sensitivity
• new physics contributions destroy SM relations

Example CKM unitarity
Vud Vub Vcd Vcb Vtd Vtb 0
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Experimental methods
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Experimental methods II
Theoretical predictions can be tested
experimentally!

• Threshold (e e-) B-factories (CLEO, BaBar,
  Belle)
• Hadronic (pp) machines (CDF, D0, B-Tev, LHCb)
• ep-machines (HERA at DESY)

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Experimental Facilities
Cornell University
SLAC
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Experimental Facilities II
KEK (Japan)
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Experimental Facilities III
FermiLab (Batavia, IL)
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Research in Particle Physics

• Theory
• Alexey Petrov
• William Rolnick

• Experiment
• Giovanni Bonvichini
• David Cinabro
• Robert Harr
• Paul Karchin
• Stephen Takach

as well as postdoctoral research associates and
graduate students
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Conclusions?

• What the particle physics is
• Why we study particles
• How we study particles
• Further questions?
• Prof. Alexey A Petrov
• Physics Research, Rm. 260
• apetrov_at_physics.wayne.edu