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Facts and Myths of the LHC, and the consequences for Astronomy

Facts and Myths of the LHC, and the consequences for Astronomy. By: Stephen Demjanenko. Outline. (Really) Quick History of Particle Physics LHC Design Detectors Goals Test Run Applications of Astrophysics. Quick History of Particle physics.

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Facts and Myths of the LHC, and the consequences for Astronomy

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  1. Facts and Myths of the LHC, and the consequences for Astronomy By: Stephen Demjanenko

  2. Outline • (Really) Quick History of Particle Physics • LHC • Design • Detectors • Goals • Test Run • Applications of Astrophysics

  3. Quick History of Particle physics • Began with the study of the atom and has now progressed to subatomic • Protons, neutrons, electrons, antimatter as well as constituents (quarks) • As of the 1970’s particle theory was condensed into the Standard Model • Predicts 252 unique particles • Since then work has been done to go beyond the Standard Model • The LHC hopes to test this as well as complete the Standard Model with the discovery of the Higgs

  4. First Particle Accelerator • John D. Cockcroft and Ernest Walton • Cavendish Laboratory • In 1930 they managed to accelerate protons across a potential of 800 kilovolts • 1932 – they split a lithium nucleus into alpha particles

  5. Major Particle Accelerators • Brookhaven National Laboratory – Relativist Heavy Ion Collider • Gold and other ions, polarized protons • Fermilab – Tevatron (proton-antiproton) • Stanford - SLAC (electron-positron) • *CERN – LHC (proton-proton) • Cornell Electron Storage Ring • Not major but its here at Cornell • 40 ft below practice football/track fields

  6. LHC Overview • Built by the European Organization for Nuclear Research (CERN) • 10,000 scientists collaborated • Cost ~ $8 billion • Generates 1 GBps of data

  7. What it is not • A weapon • Earth’s Doomsday • blackhole/wormholecreator

  8. Myths • Recently Walter L. Wagner and Luis Sancho sued CERN over the use of the LHC claiming it would destroy the planet • Did the same thing for FERMILAB • The case was thrown out

  9. Black Hole Myth • The LHC does have the ability to create a black hole • However, by Hawking radiation, all black holes are evaporating • Slow for large black holes but for any black hole the LHC could create it would evaporate in about 10-17 s • Once again, the LHC is SAFE

  10. Cosmic Rays • Cosmic rays are continually hitting the atmosphere • high energy extragalactic particles • Have energies similar/greater than the LHC can achieve • Nothing bad has happened yet • The Earth is still here • LHCf experiment

  11. So what is it? • The LHC is the most powerful particle collider ever built • Took 14 years of planning/construction • It will collide two proton beams at 14 TeV (7 TeV each beam) • Also can collider lead ions (2.74 TeV)

  12. Where is it? • Located 100m underground • Is in Switzerland and France • Located in the old LEP collider tunnel • Reused existing tunnel with a few modifications • 3.7m in width, 27km in circumference

  13. Design • 1,232 dipole magnets, 392 quadrupole magnets • Maintains circular path and focuses the beam respectively • Weigh about 27 tons each • Twin bore design used to reduce space • Also magnetically couples the two beams • 700,000 liters of liquid helium are used for cooling (1.9K) • Base energy is 450 GeV and a couple times a day they are accelerated to 7 TeV

  14. Beam Injection

  15. Detectors • Could see up to 600 million collisions per second • 6 different detectors for different types of collisions • LHCf

  16. ATLAS • General purpose detector • Higgs particle • extra dimensions (could explain weakness of gravity)? • Dark matter? • 44m long, 25m in diameter • Weighs 7,000 tons • Most complex detector ever built

  17. CMS • Also a general purpose detector • Works with ATLAS to detect the Higgs • Also looks for dark matter (WIMPs) • Weakly interacting massive particles • Also known as cold dark matter

  18. ALICE • Studies quark-gluon plasma that existed shortly after the big bang • LHC is 100,000 hotter than center of sun • Might be hot enough to free quarks from within protons • Will observe how the plasma cools and creates subatomic matter

  19. LHCb • Will try to explain the asymmetry between matter and anti-matter • There is much more matter than antimatter • Will study the bottom quark

  20. TOTEM • 440m long, 5m wide, 5m high • 20 tons • Will be located inside the CMS detector • Size of proton • Beam luminosity

  21. Goals • Understand the early universe better • Ion collider will be particularly useful for this • Find experiments to test the validity of Grand Unified Theories, and possibly string theory • Detect the predicted Higgs Boson • Expected to exist at energies this machine can reach

  22. Standard Model • Is the current accepted model of particle physics • Explains the interactions between strong, weak and electromagnetic forces • Does not include gravity • Every predicted particle has been detected except for the Higgs Boson

  23. Higgs Boson • Principle of Inertia • A body in motion will continue in the same motion given there is no applied force • Where does mass come from? • Theory suggests that inertia comes from the interaction of a body with some resistive field

  24. Higgs (cont.) • The Higgs boson makes up this field • LHC may produce a Higgs every hour • Would take 3 years to acquire enough data • Requires many events in order to statistically confirm its existence

  25. Test Run • The LHC started up on September 10th at 4:27am sending a stream of protons around at 451 GeV • There were no collisions – only one beam circulated • On September 19th the LHC was shutdown for repairs • Is expected to resume operations in spring 2009

  26. Problems with Test Run • After 2 days of operation a transformer for the liquid helium failed and part of the tunnel warmed up • Wasn’t reported for a week • Took a week to cool that section back from 4.4 K to 2.1 K

  27. Problems (cont.) • A faulty electrical connection between two magnets caused a helium leak • Caused the collider to be taken offline for the remainder of the year • 24 quadrupole and 8 dipole magnets were damaged

  28. LHC@Home • There is a distributed computing client which has been working about a year • Works to simulate protons circulating in the LHC • Helps to develop a control sequence to maintain proton containment • Could cut into the magnets, taking the accelerator offline

  29. Applications to Astronomy • Clearly the LHC is not a telescope • It does not make observations of the cosmos • It does allow us to experiment with incredibly high energies, energies seen only in the first few seconds following the big bang • Allows us to check validity of theories • We use these theories to model the evolution of the universe • Also helps us describe high energy astrophysics

  30. Applications (cont.) • As mentioned earlier the Higgs Boson is predicted to carry mass • By better understanding gravity we can figure out why gravity is much weaker than any of the three other forces

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