Parma International School on theoretical Physics 2007

MC101

A short introduction to the techniques of Monte Carlo integration. Exercises proposed during lecture are collected in this Mathematica Notebook: mc101.nb​.

Exercises

All exercises proposed here can be "solved" or checked with MadGraph / MadEvent.

MadGraph prolegomena

• Logon to the MadGraph web site and register.

• Familiarize with the code by generating a few processes in QED and QCD trying to guess which diagrams appear. What is the minimum number of jets have to be asked for in $e^+e-$ collisions so that the triple gauge vertex 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
  • VV production: pp>VV> leptons, with V=Z,W.
  • Single top + Higgs: pp>tHj (QCD=0, QED=3, j=gudsc,p=gudscb). Show that there is a large negative interference between the diagrams

QCD

• Reference: ​QCD and Collider Physics

by Keith Ellis, James Stirling, Bryan Webber (Cambridge Monographs, 1996).

• Radiation from heavy quarks: the dead cone in $e^+e- \to Q \bar Q g$.
• Spin of the gluon: Vector vs scalar in the angular correlations of $ e^{+ e}- \to$ 4 jets.
• Jets : Di-jet kinematics and rates in pp collisions.
• 3 Jets : Energy distributions in 3-jet events.
• top production : $t \bar t$ production, Tevatron vs LHC.

EW

• Reference: Lecture notes on the Standard Model and Book, by ​Giovanni Ridolfi.

• $\gamma Z$ interference in $e^+e- \to \mu^{+ \mu}-$.
• Higgs at LEP : the cross section for $e^+e- \to ZH$ at LEP2.
• Drell-Yan: rapidity asymmetry at the Tevatron and LHC.
• Spin correlations in top decay, by ​Bryan Webber.

BSM

• On-line ​SUSY LHA file generator by Sabine Kraml.
• Lorenzo Basso's model MadGraph implementation: basso.tar.gz​

LHC Phenomenology

• Analysis routines for LHE and LHCO events:
  • a Fortran-based package: MadAnalysis (​Download it here)
  • a Mathematica-based package: ​Chameleon.
• Kinematics at the LHC: single particle quantities.
• SM Higgs discovery at the LHC: Three important channels
• Simple Black Boxes: New gauge bosons

Challenges

• Black Box #1 : (Signal in various channels. Special trigger here: either at least a lepton or two energetic jets)
  • Events:Parton Level​
  • Plots: Parton level​
• Black Box #2 : (2-lepton trigger stream, ttbar background + signal A and B)
  • A Events​ Plots: Detector level​
  • B Events​ Plots: Detector level​
  • Hint: ​Here you can find a strategy to follow

-- Main.FabioMaltoni - 04 Sep 2007