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Introducing II MadGraph Automated Tree-Level Feynman Diagram and Helicity Amplitude Generation +
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Outline What is MadGraph? What’s New in MadGraph II? Why use MadGraph? Example: Top production at FNAL Future Plans
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What is MadGraph? Fortran computer program that: –Generates fortran helicity code (HELAS) to calculate tree level matrix elements –Includes color/symmetry factors –Creates postscript file of Feynman diagrams.
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What’s New in MadGraph II? User defined models –Standard Model –MSSM Unlimited external particles –Within reason! (12?) Color Flow Information –Helps interface with HERWIG/PYTHIA Required/Excluded particles –uu~ > W+ W- b b~ g –uu~ > tt~ >W+ W- b b~ g // Z
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Powerful (Lots of diagrams/external particles) Relatively fast –Amplitude generation –Matrix element evaluation N not N 2 Keeps Spin Information –Easy to add decay chains Why use MadGraph? User interface ………NOT
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Top Pairs at Fermilab Signaluu~ > tt~ > e+ ve b e- ve~ b~ Background: uu~ > e+ ve b e- ve~ b~ Radiation: uu~ > tt~ > e+ ve b e- ve~ b~ g
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Signal (1) uu~ > tt~ > e+ ve b e- ve~ b~
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Feynman Diagrams Background (66)
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Signal+Radiation (7)
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Future of MadGraph Tell me what you want! Improved Interface –User –PYTHIA/HERWIG –Integration Improved Speed
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Signal+Radiation (7)
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Feynman Diagrams Background (66)
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Top Pairs at Fermilab
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