​Signaling the Arrival of the LHC Era Top Quark Physics at the LHC

Authors

• Fabio Maltoni (lecturer)

Lectures

Find the pdf of the 2 x 1.5h lectures here

References

• ​QCD and Collider Physics by Keith Ellis, James Stirling, Bryan Webber (Cambridge Monographs, 1996). General introduction QCD. The section on top is an easy and efficient reading to learn the basics.

• ​Top physics at the LHC, by Beneke et al. : A complete document, though a bit outdated, that covers many of the interestings studies that will be performed at the LHC. A very useful reference.

• ​Top Physics at the LHC, by Werner Bernreuther : A nice and up-to-date overview on top physics at the LHC. It has also a complete reference list that can be used for further studies.

• ​Top mass definition, by M. Smith and S.Willenbrock. This is an easy and very clear discussion that it will make you appreciate the subtleties associated to a meaningful definition of a mass of a quark.

Exercises

Decay

• Top width: Calculate the width of the top quark.
• Radiation from heavy quarks: the dead cone in $e^+e- \to Q \bar Q g$.
• W+ polarization in top decays.

Production

• top production : $t \bar t$ production and single top at Tevatron vs LHC.
• scalar vs fermion top cross sections at hadron colliders : Compare the production of scalar and fermion heavy color triplets in hadron collisions.
• Spin Correlations in top production

Light material on the heaviest quark

• Movies
  • ​Interactive Flash version Note you may want to zoom in!
  • ​Fast movie (.avi) of collision
  • ​Guided movie (.mov) of collision
• Review
  • Secrets of a heavyweight​, by Kurt Riesselmann.

Familiarize with MadGraph

A brief tutorial on MadGraph / MadEvent can be found here​.

• Logon to the MadGraph web site and register: ​http://madgraph.hep.uiuc.edu.
• Familiarize with the code by generating a few processes in QED + QCD trying to guess which diagrams appear.
• Look at the new physics models and check the particle and interactions content.
• Generate events for a few selected processes and look at the plots:
  • ttbar production with decays: pp>tt~>bb~mu+e-ve~vm
  • Single top + Higgs: pp>tHj (QCD=0, QED=3, j=gudsc,p=gudscb). Show that there is a large negative interference between the diagrams.

Analysis Tools

• a Fortran-based package: MadAnalysis (​Download it here)
• a Mathematica-based package: ​Chameleon.

MC101

For those interested in Monte Carlo techniques, here is a short Mathematica course with applications to top physics:

• Write the simplest integration function based on the definition of average and error
• Importance sampling via an analytic transformation
• Von Neumann's rejection method : plain and improved
• Phase space for 1 -> n particles
• Vegas
• Top decay : comparison among the various methods
• qq -> tt production

All exercises are presented and solved this Mathematica Notebook: mc101.nb​. Reference: ​Introduction to MC methods, by ​Stefan Weinzierl

-- Main.FabioMaltoni - 2010-07-21