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Particle Physics and LHC Physics

Particle Physics and LHC Physics. David Krofcheck Canterbury Teachers Workshop July 18 th. The place to be for high energy physicists. Lac Léman. Jura. CERN (FR). Geneva airport. CERN (CH). Large Hadron Collider. 27 km (17 miles) circumference

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Particle Physics and LHC Physics

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  1. Particle Physics and LHC Physics David Krofcheck Canterbury Teachers Workshop July 18th Canterbury Teachers Workshop

  2. The place to be for high energy physicists Lac Léman Jura CERN (FR) Geneva airport CERN (CH)

  3. Large Hadron Collider • 27 km (17 miles) circumference • 1600 superconducting magnets at 1.9° K (-271.3° C or – 459.7° F) • 120 tonnes of liquid helium • Accelerates beams of protons to 99.9999991% the speed of light Large Hadron Collider

  4. The CMS detector at the Large Hadron Collider New Zealand Hadron Calorimeter EM Calorimeter Beam Scintillator Counters Forward Calorimeter CASTOR ZDC Tracker (Pixels and Strips) Muon Endcaps Pitt/CMU July 2011 Muon Barrel

  5. The really important CMS detectors Pitt/CMU July 2011

  6. What is matter? Aristotle : all matter is made up of various combinations of Earth, air, fire and water This belief about the nature of matter lasted for 2000 years solids gases change liquids Canterbury Teachers Workshop

  7. Development of the Atomic Theory Aristotle Democritus John Dalton Canterbury Teachers Workshop Lucretius

  8. Ideas about Atoms 1800’s John Dalton – meteorologist and teacher- successfully explained chemical reactions by proposing all matter is made up of atoms.- BUT they had no direct evidence! Canterbury Teachers Workshop 8

  9. PeriodicTable Similar chemicalproperties DmitriMendeleev Russian 1834-1907 Canterbury Teachers Workshop

  10. Atoms PeriodicTable Rutherford (1909) Bohr (1913) ? Canterbury Teachers Workshop

  11. ... proton neutron electron •Are thesetheelementaryparticles, ? • Are theycomposed of even more elementaryparticles?? • Particle and Nuclear Physics are thestudiestoanswerthisquestion Canterbury Teachers Workshop

  12. MatterParticles 1932 p, n, e 1937 μ ν 1940s mesonsπ, K 1950s particlesΛ, Δ, Σ, ... …hundreds of new particleswerediscovered! Canterbury Teachers Workshop

  13. u u d d quarks d u proton neutron In 1964 the idea of quarks wasproposed… These were elementary particle of, fractional electric charge, different flavours Zweig Gell-Mann Canterbury Teachers Workshop

  14. q(u) =+2/3 d u q(p) =+1 q(d) =-1/3 u d u d Whatisthecomposition of theproton ...and of theneutron q(n) =-1/3 - 1/3 + 2/3=0 Canterbury Teachers Workshop

  15. u u d Whatgluesthe quarks together? Gluons, of course proton Canterbury Teachers Workshop

  16. Elementaryparticles of matter 1897 1st family: u, d, e- , e 2nd family: c, s, - ,  3rd family: t, b, - ,  leptons 1995 Canterbury Teachers Workshop Higgs 4 July, 2012

  17. Antimatter Every particle has its antiparticle, of the same mass but opposite quantum numbers eg. electron, e- : q(e-) =-1 , spin = -1/2 , m(e-) = 9.110-28 gr. positron, e+ : q(e+) =+1 , spin = +1/2 , m(e+) = 9.110-28 gr. Canterbury Teachers Workshop

  18. 4 basicinteractions . . . . . . n  p + e- + ne d  u + e- + ne All these interactions are manifestations of only 10-40 10-2 átomo Gravitational Force Electromagnetic Force 1 10-5 nuclei Strong Colour Force Weak Force

  19. Mediating Particle Still not detected experimentally

  20. Example: Electromagnetic interaction http://www.cerimes.education.fr/

  21. The Fundamental Interactions are produced by the exchange of a particle mediator http://www.cerimes.education.fr/ The particles of matter interact across a distance by exchanging a “messenger” particle The interaction range decreases as the mass of the messenger particle increases.

  22. Standard Model of Particle Physics • Messengers • interactions leptons In a quantum description of matter and the laws of interaction between them still do not know how to incorporate gravitation, but the rest of interactions are well described by a mathematical theory, the Standard Model, able to make predictions that have been confirmed in experiments.

  23. Symmetry Components of matter Standard Model Interactions (~1980) This model requires that the particle messengers are massless, But the W and Z are very heavy!! problem of theorigin of mass

  24. HiggsBoson • The British physicist Dr. Peter Higgs proposed (1964) the so-called Higgs mechanism: • All the particles would be generated in the Big Bang without mass, but by interacting with the field created by the Higgs particle, the particles would acquire mass, the greater, the greater the interaction. This field would fill the whole universe. • Interaction with the Higgs field • Friction with a viscous liquid ≡

  25. HiggsBoson The British physicist Dr. Peter Higgs proposed (1964) the so-called Higgs mechanism: All the particles would be generated in the Big Bang without mass, but by interacting with the field created by the Higgs particle, the particles would acquire mass, the greater, the greater the interaction. This field would fill the whole universe. Friction with a viscous liquid Interaction with the Higgs field ≡ Unico “Higgs” observado hasta ahora en un experimento…el propio Dr. Higgs!!

  26. HiggsBoson This particle predicted has not yet been unambiguously detected in experiments, hopefully we are hot on the trail! . ≡ A recentview of a Higgs at the CMS experiment

  27. !!?? H  Z0Z0  μ+μ-μ+μ-

  28. Gauge Bosons – Z0 First detection in HI collisions! First step is to find Z0 bosons in PbPb collisions • Z0→μ+μ - observed for the first time • in HI collisions!

  29. Z0 →e+e- event candidate Z0→e+e- observed for the first time in HI collisions!

  30. lead + lead collisions may liberate quarks

  31. Jet production in pp collisions jet-jet correlation in QCD “vacuum” Jet Jet Dijet Probes of Hot Nuclear Matter at the LHC

  32. Jet production in PbPbcollisions • jet-jet correlation in QCD “medium” γ – jet correlation to probe the medium? Dijet Probes of Hot Nuclear Matter at the LHC

  33. E-ΔΕ1 E-ΔΕ2 • Dijet imbalance in PbPbcollisions Δφ Phys. Rev. C 84, 024906 (2011) Dijet Probes of Hot Nuclear Matter at the LHC

  34. Jet production in PbPb collisions gamma-jet correlation in QCD “medium” Gamma Nuclear remnant Nuclear remnant Dijet Probes of Hot Nuclear Matter at the LHC

  35. Observed momentum imbalance in γ– jet correlation Submitted to PLB, arXiv:1205.0206 • Momentum ratio shifts/decreases with centrality • jets shifting below the 30 GeV pT threshold not included Dijet Probes of Hot Nuclear Matter at the LHC

  36. Energy Units! Electron Volt – Energy gained by an electron when accelerated in an electric field through a potential difference of 1 volt. 1 eV = 1 electron Volt Energy to ionise hydrogen = 13.6 eV 1 keV(kilo) = 1,000 eV = 103 eV Medical X-ray ~ 200 keV 1 MeV(Mega) = 1,000,000 eV = 106 eV Alpha particle decay of uranium 4.2 MeV 1 GeV(Giga) = 1,000,000,000 eV = 109 eV LEP collider beam (1989-2000) = 45 GeV 1 TeV(Tera) = 1,000,000,000,000 eV = 1012 eV Highest energy accelerator in world = 1 TeV (Tevatron) Highest energies found in cosmic rays (>1020 eV)

  37. Interactionsbetweenmatterparticles

  38. Why are there so manydifferentsubstances in theworld? Canterbury Teachers Workshop

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