Mad Graph Mad Event Automated TreeLevel Feynman Diagram

Mad. Graph + Mad. Event + Automated Tree-Level Feynman Diagram, Helicity Amplitude, and Event Generation Tim Stelzer Fabio Maltoni

Outline • • • What is Mad. Graph? What’s New in Mad. Graph II? Example: W+ 3 jets FNAL What is Mad. Event? Capability Future

What is Mad. Graph? • 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.

New in Mad. Graph II! • User defined models – Standard Model – MSSM • Unlimited external particles – Within reason! (12? ) • Color Flow Information – Helps interface with HERWIG/PYTHIA • Jets + Required/Excluded particles – pp ~ > W+ W- b b~ j – pp~ > tt~ >W+ W- b b~ j // Z • Phase Space Information

PP → + W 3 jets • Enter Process: pp > e+ ve jjj • Enter QCD Order: 4 • Enter QED Order: 2 (…… wait 2 minutes) • Generated 53 sub processes

What is Mad. Event? • Fortran computer program that: – Uses output from Mad. Graph – Generates • Cross sections • Events (Les Houche format) – W+ 3 jets: • First 10, 000 unweighted events about 30 minutes.

Examples: Vector Bosons

Examples: Heavy Quarks

What about W+8 jets? • Current Limitations – PP -> W+ 5 jets (1 week) – 9999 diagrams (1000 is nice) – 10 external particles (8 is easy) – 7 summed particles (protons/jets) • Future Improvements – Housekeeping – Phase Space (factor of 10 in speed!)