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Quantum Chromodynamics. John Christie & Jude Rowe Santa Rosa Junior College Physics 43 Spring 2009. What we will be discussing. A Brief History of QCD What is QCD? Implications. History of QCD. Early 1950’s: Discovery of Hadrons inside “Elementary Particles”
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Quantum Chromodynamics John Christie & Jude Rowe Santa Rosa Junior College Physics 43 Spring 2009
What we will be discussing • A Brief History of QCD • What is QCD? • Implications
History of QCD • Early 1950’s: Discovery of Hadrons inside “Elementary Particles” • Attempts to sort particles using QED, strangeness, led to Eightfold Way • 1963: Theory of smaller particles inside Hadrons called partons, or Quarks.
Creation of QCD Δ++ particle and Ω- had three quarks with parallel spin, violating the Pauli exclusion principle • Proposal by Han, Nambu, and Greenburg that these quarks had an additional degree of freedom, “color charge”. • Experiments later verified existence of gluons, exchange particles that carry said “color charge”
What is QCD? • QCD was created based on QED’s inability to explain all quark interactions Eightfold Way of Mesons Color Chart
Numerical Analysis • To calculate QCD we use equations similar to Boltzman equations • …faster computers are required in order to mathematically model and compute these interactions
Implications of QCD • Defines a new quantum number through Asymptotic freedom • Grand Unified Theory • Increased demand on technology for research and verification of QCD
Proving QCD? • Confinement prevents direct observation of free Quarks and Gluons • Some verification of QCD using CERN (a few percent) • Lattice QCD computations theoretically predict but not analytically prove QCD theory • Phases of Quark Matter
Phases of Quark Matter Temperature Chemical Potential
Resources • http://arxiv.org/PS_cache/hep-ph/pdf/0408/0408206v1.pdf • http://www.experiencefestival.com/a/Quantum_chromodynamics_-_History/id/4694211 • http://www.aps.org/publications/apsnews/200412/nobel.cfm • http://www.aps.org/publications/apsnews/200403/qcd.cfm • http://www.aps.org/units/ghp/gallery/qcd.cfm • http://google1.aps.org/search?q=QCD+history&btnG=Google+Search&entqr=0&output=xml_no_dtd&sort=date%3AD%3AL%3Ad1&entsp=a&client=default_frontend&ud=1&y=0&oe=UTF-8&ie=UTF-8&proxystylesheet=default_frontend&x=0&site=default_collection • http://www-spires.slac.stanford.edu/cgi-bin/spiface/find/hep/www?FORMAT=WWW&rawcmd=fin+au+Altarelli%2CG • http://www-d0.fnal.gov/~d0qcd/QCD_theorists.html • http://www-d0.fnal.gov/public/links/index.html • http://www-d0.fnal.gov/Run2Physics/WWW/results/summary.htm • http://www-d0.fnal.gov/Run2Physics/qcd/ • http://physics.nmt.edu/~raymond/classes/ph13xbook/node210.html • http://en.wikipedia.org/wiki/Quantum_chromodynamics • Thorton, Stephen T. Modern Physics for Scientists and Engineers. 3rd Ed.