LHC New era Large Hadron Collider protons protons

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LHC New era ?Large Hadron Collider (protons
protons)

• C.H. Wang/nuu

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Outline

• What is LHC?
• CERN Accelerator
• Recent News of LHC
• History of Particle Physics
• What Comes from LHC
• Summary

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Budget/Size/Man Power/Fact

• The largest machine in the world...
• Circumference 26659 m
• Cost 3 billion Euro (machine only)/6.0 billion
  (15 detector)
• The fastest racetrack on the planet...
• v 99.9999991c ? 7 TeV per proton
• The emptiest space in the Solar System...
• The internal pressure of the LHC is 10-13 atm,
  ten times less than the pressure on the Moon!

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• The hottest spots in the galaxy, but even colder
  than outer space...
• When two beams of protons collide, they will
  generate temperatures more than 100 000 times
  hotter than the heart of the Sun.
• The 'cryogenic distribution system', which
  circulates superfluid helium around the
  accelerator ring, keeps the LHC at a super cool
  temperature of -271.3C (1.9 K) even colder
  than outer space!

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• The biggest and most sophisticated detectors ever
  built...
• Detector (scientists)
• CMS (2000), ATLAS(2000), ALICE(1000),
  LHCb(700)
• 600 million collisions per second
• The most powerful supercomputer system in the
  world...
• The data recorded by each of the big experiments
  at the LHC will fill around 100 000 dual layer
  DVDs every year.
• ? GRID

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First Week of LHChttp//public.web.cern.ch/public
/

• LHC started the beams on 10 September.
• On 18 September 2008, LHC successfully got beams
  around the ring in both directions on the first
  day with several hundred orbits being achieved.
• The next step in the commissioning process is to
  bring in the radio-frequency (RF) system that
  keeps the beams bunched, rather than spreading
  out around the ring, and will eventually
  accelerate them to 7 TeV.
• Next To collide the beams !

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Last Week of LHC

• Geneva, 23 September 2008. Investigations at
  CERN1 following a large helium leak into sector
  3-4 of the Large Hadron Collider (LHC) tunnel
  have indicated that the most likely cause of the
  incident was a faulty electrical connection
  between two of the accelerators magnets.
• Before a full understanding of the incident can
  be established, however, the sector has to be
  brought to room temperature and the magnets
  involved opened up for inspection. This will take
  three to four weeks.
• Restart the accelerator complex to early spring
  2009. LHC beams will then follow.

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History of Particle Physics

• What are the Elementary Constituents of Matter?
• What are the forces that control their behaviour
  at
• the most basic level?

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1930 - 1950

• electron/proton/neutron/neutrino/photon..
• anti-matter
• Proposed in 1928 and discovered in 1932
• positrons (balloon flight) Carl Anderson ,
  PR43, 491 (1933)

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• Neutron discovered by James Chadwick /1932
• Fermi theory of beta decay n -gt p e- ?e
  /1933
• (Weak Interaction)
• Yukawas meson hypothesis on nuclear force /1935
• m(muon) lepton discovered by Carl Anderson /1937
  (Yukawa?)
• Charged p meson discovered p -gt m nm /1946
• Neutral p meson discovered po -gt g g /1950

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• By 1950
• QED (Quantum Electrodynamics) -- quantum theory
  of electrodynamics. Charged particles interact
  via exchange of photons.
• Richard Feymann/ Julian Schwinger/ Tomonaga

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• In 1947 kaons were discovered in the cosmic rays.
  At first, people thought kaons should have
  decayed to pions relatively rapidly. But this was
  not the case. And scientists did think this
  strange. And so the kaon was assigned a property
  called "strange."
• Discovery of
• anti-proton in 1955.
• In 1956, neutrino was detected directly.

??e ? p ? e n
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W h a t a j u n g l e !
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• From Fermi Lab
• http//www-donut.fnal.gov/web_pages/standardmodel
  pg/TheStandardModel.html
• -1956-57 Tsung-Dao Lee and Chen Ning Yang propose
  parity non-conservation in certain sub-atomic
  processes, which is confirmed by experimentalist
  Chien-Shiung Wu

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• -1962 The first experimental observation of the
  muon neutrino
• -1964 Quarks are proposed by Murray Gell-Mann and
  George Zweig
• -1964 W- was discovered.
• -1967 Steven Weinberg, Sheldon Glashow
  (collaboration) and Abdus Salam (independent)
  create the electro-weak theory, unifying the
  electromagnetic and weak nuclear force (they win
  Nobel prizes in 1979)
• -1970-73 Standard model of particle physics is
  developed (QCD)
• -1974 The charmed quark is observed
• -1975 Evidence of the tau lepton is found
• -1977 Experimenters find proof of the bottom quark

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Belle Detector
Aerogel Cherenkov cnt.
n1.0151.030
SC solenoid 1.5T
3.5 GeV e
CsI(Tl) 16X0
TOF conter
8 GeV e-
Central Drift Chamber small cell He/C2H6
Si vtx. det. 3/4 lyr. DSSD
m / KL detection 14/15 lyr. RPCFe
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• -1983 Carlo Rubbia discovers the W and Z bosons,
  mediators of the weak-force
• -1994 Planning for LHC (Large Hadron Collider) at
  CERN begins
• -1995 Evidence for the top quark, the final
  undiscovered quark, is found at Fermilab
• -2000 The tau neutrino, the last piece to the
  standard model, (with the exceptopm of the higgs
  particle) is observed at Fermilab

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Size 46 m long, 25 m high and 25 m wide. The
ATLAS detector is the largest volume particle
detector ever constructed. Weight 7000 tonnes
Size 21 m long, 15 m wide and 15 m high.
Weight 12 500 tonnes
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The Standard Model of Particle Physics
(Electroweak Strong)

• Fundamental Particles quarks leptons
• In weak decays, quarks will change flavors.
  (quark mixing)
• Source of the mass Higgs Boson

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Proton-Proton Collision (LHC)

• What is our plan?
• Search for Higgs!
• H -gt Z0 Z0 / Z0 -gt ll-
• What is our dream?
• New Particles!
• Clues for new physics!

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Summary

• LHC successfully ejects and maintain the beams
  inside the beam pipe.
• Maintenance is a challenge issue.
• Plan to collide beams middle next year.
• Hope for the unexpected results!