Recreating the Early Universe at the LHC

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Recreating the Early Universe at the LHC

• King Edwards School, Bath

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Particle Physics

• Particle physics aims to answer the BIG
  questions about the Universe by studying space
  and matter at its smallest level
• If a helium atom was the size of a large city,
  each proton and neutron would be the size of a
  person, and each quark and electron would be
  smaller than a tiny freckle.

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The Standard Model Ingredients for a Universe
Fundamental forces
Fundamental particles
How can scientists probe matter at subatomic
level?
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Particle Acceleratora.k.a. the Particle Smasher

• A particle smasher accelerates particles to high
  speeds and collides them.
• The particles then decay into subatomic parts and
  emit radiation.
• Their paths are detected

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CERN European Organisation for Nuclear Research
First experiments carried out at CERN concerned
the inside of the atom hence organisation for
Nuclear Research 2,500 people work at CERN.
However, thousands more scientists across the
globe are connected to research being carried out
here. Revolutionary technology has been created
at CERN - The Web was invented at CERN in
1990 The LHC will be switched on for the first
time in May 2008!
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Recreating the early Universe Why?

• Scientific curiosity Answering questions about
  Life, the Universe and Everything!
• Scientific ambition how far can experimental
  work take us?
• Technology developed for the LHC project could
  have spin-offs in medicine, computing and many
  other fields.
• Develop a Grand Unified Theory explaining the
  workings of the universe

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Anaxagoras of Clazomenae
0 AD
1000 AD
Present Day
Widely recognised as the first major Greek
philosopher come scientist.
There is no smallest among the small and no
largest among the large, but always something
still smaller and still larger
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Empedocles of Acragas
1000 AD
0 AD
Present Day
Held the belief that all existence consisted of 4
elements.
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Democritus of Abdera
1000 AD
0 AD
Present Day
An advocate of the atomist doctrine

• All matter is made up of indivisible particles
  (atoms) in a great void.

• Atoms are infinite in number and are perfectly
  solid.

Nothing exists except atoms and empty space
everything else is opinion.
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John Dalton
0 AD
1000 AD
Present Day

• Experimentally deduced the existence of atoms
  through studying gases.

• Proposed a similar but refined version of
  Democritus atomic theory.

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George Stoney
0 AD
1000 AD
Present Day

• The first to conceive the existence of particles
  of electricity.

• Accurately calculated the electrons mass.

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Joseph Thomson
0 AD
1000 AD
Present Day

• Proved the existence of electrons by studying
  cathode-ray tubes.

• Measured its size and charge

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Max Planck
0 AD
1000 AD
Present Day

• Founding father of Quantum Theory.

• The Planck constant, h (h-bar), is a fundamental
  physical constant used in quantum mechanics.

6.626 10-34 joule-seconds
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Ernest Rutherford
0 AD
1000 AD
Present Day

• Introduced the concept of an atomic nucleus and
  experimentally proved its existence.

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Albert Einstein
0 AD
1000 AD
Present Day

• Introduced the concept of photons, leading to
  the modern view of wave-particle duality in light.

• Proved that nothing can reach the speed of light
  (E mc2), or even catch up with it.

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Werner Heisenberg
0 AD
1000 AD
Present Day

• Developed quantum mechanics irrevocably with his
  Uncertainty Principle

- It is impossible to locate both the position
and the momentum of a particle with precision.
- Probability distributions must be used to
estimate these factors.
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Current Knowledge
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The Big Bang

• This occurred about 14 billion years ago
• The universe began from a miniscule point
• The fundamental forces were combined at this stage

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The Hubble Telescope
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Gravity

• Why is gravity so much weaker than the other
  fundamental forces?
• Are extra dimensions the answer?

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Particle acceleration

• A step-by-step guide

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Getting the Energy

• Electrons slow down as they travel through the
  Klystron, emitting microwaves as their speed
  varies.

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2. Particle generation

• Particles are knocked from their atoms using
  lasers or electron guns.

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3. Acceleration

• Particles accelerated by the alternating field,
  with the cavity walls shielding from the
  decelerating effects of the microwaves.

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4. Aiming the particles

• The magnets varyingly attract and repel the
  particles extremely quickly, with the effect that
  they remain travelling in a straight line.

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5. The Collision

• The two groups of particles collide. The very
  high energy of the collision is such that the
  particles smash apart in to even smaller
  sub-particles, quarks in our case.

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µ-
p
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6. Detecting the particles

• Any charged or high energy particles will
  ionise atoms they come into contact with, and we
  can detect the trails of ions these particles
  leave behind them, e.g. with a cloud or bubble
  chamber.

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Cloud and Bubble chambers

• The particles ionise the atoms they travel past,
  which in turn attract the particles which visibly
  change their state, allowing us to see the trails
  of the particles.

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Seeing different particles

• The particles curve different ways, at varying
  amounts and velocities. Analysing these variables
  allow us to work out what kind of particle it is.

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What are we looking for?

• Standard model
• Higgs Boson
• Other particles
• Strangelets
• Micro black holes
• Magnetic monopoles
• Supersymmetric particles

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Standard Model

• It predicts that one more particle is to be
  discovered, the Higgs Boson.
• By completing the standard model, some physicists
  hope to extend it into a theory of everything.

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Higgs Boson

• It would provide the mechanism by which particles
  acquire mass.
• Accelerators have not produced a Higgs boson.
• In order for physicists to develop their
  understanding of the matter, there needs to be
  progress in the search for the Higgs boson.

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Other Particles

• Other theorized particles may be produced at the
  LHC, and searches for some of these have been
  planned.
• Some examples of these particles are
• Strangelets
• Micro black holes
• Magnetic monopoles
• Supersymmetric particles

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Where will it lead?

• Grand Unified Theory
• Why is Gravity So Weak?
• Technological Developments
• International Linear Collider

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Grand Unified Theory

• Physicists have linked two of the four
  fundamental forces with electroweak theory (in
  1979).
• Grand unification theories (GUTs) have tried to
  link a strong force to these two forces.
• The creation of a GUT would be a breakthrough in
  particle physics.

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Why is Gravity So Weak?

• The Higgs boson may help to explain why gravity
  is so much weaker than the other three
  fundamental forces.
• By developing a greater understanding of where
  the fundamental forces originated from,
  physicists hope to understand how and why they
  differ.

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Technological Developments

• The creation of the LHC has led to many
  technological developments, as new equipment is
  needed to fulfil functions that have not been
  necessary before.
• Examples include
• Positron emission tomography (PET)
• A nuclear imaging technique used in medicine to
  create a 3D image of functional processes in the
  body
• PET cameras were first used in CERN in the 1970s

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Technological Developments

• World Wide Web
• Created by Sir Tim Berners-Lee, in 1989
• At that time he was working at CERN and used the
  service to share information with other academics
• The GRID
• A service used to share computer power and data
  storage capacity over the Internet
• The data will be produced at about 10 Petabytes a
  year.

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International Linear Collider (ILC)

• The ILC is a proposed electron-positron collider,
  which will work with the LHC, to provide more
  precision and help discover more.
• They will work together to understand particle
  physics beyond the standard model.