Re-creating the Big Bang

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Re-creating the Big Bang
Experiments at the Large Hadron Collider
Albert Einstein
Ernest Walton
Dr Cormac O Raifeartaigh (WIT)
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Overview

• I What
• II Why
• III How
• IV A brief history of atoms
• V Expectations

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I The Large Hadron Collider

• A particle accelerator
• Atom smasher
• Particles created
• Detected

LHC at CERN, Geneva
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How

• High speed proton beams
• Opposite directions - collisions
• Huge energy of collision
• Create short-lived particles
• Detection and measurement

E mc2
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HOW

• 27 km
• Energy 14 TeV
• Low temp 1.6 K
• Ultra high vacuum

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Why

• Explore fundamental constituents of matter
• Investigate forces that hold matter together
• Glimpse of early universe
• Highest energy since BB

Are the forces of the universe related ?
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Newton (1642-1727)
Newtons gravity

• Planet orbits due to gravity

• Gravity caused by suns mass

• Terrestrial gravity due to earths mass

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Four forces of nature

• Force of gravity
• Holds cosmos together
• Long range
• Electromagnetic force
• Holds atoms together
• Strong nuclear force holds nucleus together
• Weak nuclear force radioactivity

The atom
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A brief history of atoms

• Democritus (600 BC) matter made of atoms

• Dalton (19th ct)

• Mendeleev (19th ct)

chemical reactions
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A brief history of atoms

• Maxwell (19th ct) atomic theory of gases
• Einstein (1905) Brownian motion due to atoms?
• Perrin (1908) verified

Brownian motion
Perrin
Einstein
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The atomic nucleus

• Most projectiles through
• A few deflected backwards
• Atom has nucleus
• Electrons outside

Rutherford (1911)
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Nuclear model of the atom
Atom

• Nucleus (ve)
• Electrons (-ve) orbiting
• Force electromagnetic

Nucleus

• Protons (1909)
• Nucleus (1911)
• Neutrons (1932)?

nNu
Nuclear force stronger than electromagnetic?
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Splitting the nucleus
Cockcroft and Walton particle accelerator Partic
les used to split the nucleus (1932)
H Li He He
Verified mass-energy (E mc2) Verified quantum
tunnelling
Nobel prize (1956)
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Nuclear fission

• Meitner, Hahn nuclear fission
• Energy released

• Chain reaction
• Nuclear bomb

• Nuclear power
• Nuclear power stations

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New particles

• Cosmic rays

New particle accelerators
cyclotron
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Particle Zoo
Over 100 particles
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The quark model

• New periodic table
• New fundamental particle
• Proton not fundamental
• Inner structure
• Symmetry arguments
• Quarks

Murray Gellmann
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Quarks and leptons

• Six different quarks
• (u,d,s,c,t,b)
• Six leptons
• (e, µ, t, ?e, ?µ, ?t)
• Particles of matter fermions
• Two extra generations

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The Standard Model

• Matter leptons and quarks
• Force carriers bosons

• EM weak electroweak
• Strong force quark force

Higgs field Particle masses Higgs boson
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LHC expectations

• Higgs boson
• 120-180 GeV
• Set by mass of top quark, Z boson
• Explain masses for other particles

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Beyond the standard model

• Unification of 3 forces
• Grand unified theory
• Supersymmetry
• Supersymmetric particles?
• Unification of 4 forces
• Theory of everything
• String theory
• Extra dimensions

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LHC and cosmology

• LHC photo of early U

• v 1. Exotic particles
• v 2. Unification of forces
• 3. Nature of dark matter?
• 4. Missing antimatter?

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3. Summary

• Higgs boson
• Close chapter on SM
• Supersymmetric particles
• Open chapter on unification
• WIMPS
• Explain Dark Matter
• Unexpected particles
• Revise theory

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Epilogue CERN
Organization for Nuclear research

• World centre for particle physics
• 20 member states
• 10 associate states
• Ireland not a member

No particle physics in Ireland