What are we made of ?

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What are we made of ?
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Neutrinos
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Building a Particle Collider
CERN LEP, LHC
The ring is 27km round and on average 100m
underground
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We need particles
The hydrogen source for protons at the LHC
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We need to accelerate them
Van de Graff Generator Plasma Ball
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LHC RF cavity
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We need to control them
Cathode ray tube magnets
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Accelerator Physics
E m c
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Electron positron annihilation to a photon allows
us to convert their energy to look for all the
particles that make up nature
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The Large Hadron Collider collides the nuclei of
atoms with 10 times higher energy than has
previously been achieved (14 TeV)
LHC
1232, 35 ton, superconducting dipole magnets
accelerate ions and focus them into bunches for
collision
36,000 tons of coolant below 2K!
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Proton-Proton collisions (hydrogen atom nuclei)
14 TeV centre of mass energy
100 billion protons per bunch 20 collisions per
crossing 1 crossing every 25ns 600 million
collisions per second
To store all collision data would involve storing
10 Petabytes of data a year ie a 20km high stack
of CDs more than can be made
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Detection
Cloud Chamber
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Calorimeters

• Crystal, glass, liquid
• Acts as absorber and scintillator
• Light detected by photodetector
• E.g. PbWO4

vertex detectors look for inflight decays of
particles
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What have we found?
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What have we found?
Why do otherwise identical particles have
different masses?
There must be a new force that interacts
differently with the muon and electron its
quanta are the higgs boson more in the final
lecture