| 1 | |
| 2 | |
| 3 | == QCD at the LHC, Frascati 2010 == |
| 4 | |
| 5 | Two lectures are given on QCD at the LHC. |
| 6 | |
| 7 | 1. Accurate QCD : Fixed order calculations from LO to NNLO |
| 8 | 1. Useful QCD : Parton Showers |
| 9 | 1. Best QCD : Merging FO calculations with PS at LO and NLO. |
| 10 | |
| 11 | The PDF of the lectures can be found [attachment:maltoni-frascati-2010.pdf here]. |
| 12 | |
| 13 | The examples and exercises are related to physics at the LHC. |
| 14 | === Basic aspects of QCD === |
| 15 | ===== Various Tests and exercises ===== |
| 16 | |
| 17 | A collection of test, exercises, and web applications on pQCD can be found in [attachment:QCD-exercises.pdf QCD-exercises.pdf]. |
| 18 | |
| 19 | ===== Exercise on recursive relations ===== |
| 20 | |
| 21 | Think about the computation of q \bar q + n \gamma in a recursive way, by trying not calculate the same quantities twice. Show that the complexity of the calculation goes from n! (factorial) to 2^{n-1} (exponential) . |
| 22 | === Going NLO === |
| 23 | |
| 24 | 1. pp>H at LO (1-loop): details of the calculation (Mathematica Notebook) [attachment:HiggsGG-LO-mtfinite.nb HiggsGG-LO-mtfinite.nb] |
| 25 | 1. pp>H at NLO: details of the calculation (Mathematica Notebook) [attachment:HiggsGG-NLO.nb higgsGG-NLO.nb] |
| 26 | 1. pp>H at NLO: cross section evaluation for the LHC (Mathematica Notebook+PDF libraries to be compiled) [attachment:phenHiggs.tar.gz phenHiggs.tar.gz]. |
| 27 | |
| 28 | A summary of the results can be found in [attachment:Higgs.pdf Higgs.pdf]. |
| 29 | |
| 30 | === Selected exercises on QCD that can be solved with a Matrix Element generator. === |
| 31 | |
| 32 | * [:DeadCone:Radiation from heavy quarks]: the dead cone in %$e^+e^- \to Q \bar Q g$%. |
| 33 | * [:GluonSpin:Spin of the gluon]: Vector vs scalar in the angular correlations of %$ e^+ e^- \to$% 4 jets. |
| 34 | * [:2Jets:Jets] : Di-jet kinematics and rates in pp collisions. |
| 35 | * [:3Jets:3 Jets] : Energy distributions in 3-jet events in pp collisions. |
| 36 | * [:tt:top production] : %$t \bar t$% production, Tevatron vs LHC. |
| 37 | * [:WAsymm:Drell-Yan]: rapidity asymmetry at the Tevatron and LHC. |
| 38 | * [:TopDecaySpinCorrelations: Spin correlations in top decay], by [http://www.hep.phy.cam.ac.uk/theory/webber/ Bryan Webber]. |
| 39 | |
| 40 | === Monte Carlo integration === |
| 41 | |
| 42 | A short introduction to the techniques of Monte Carlo integration. Exercises proposed during lecture are collected in this Mathematica Notebook: [attachment:mc101.nb mc101.nb]. |
| 43 | |
| 44 | === LHC Phenomenology === |
| 45 | |
| 46 | * [:DiscoverTheHiggs:SM Higgs discovery at the LHC]: Three important channels |
| 47 | * [:WarmingUpChallenge:Simple Black Boxes]: New gauge bosons |
| 48 | |
| 49 | === How to familiarize with Software.MadGraph === |
| 50 | |
| 51 | All exercises proposed can be "solved" or checked with Software.MadGraph / Software.MadEvent. Here is how to familiarize with the code. |
| 52 | |
| 53 | * Logon to the Software.MadGraph web site and register. |
| 54 | |
| 55 | * Familiarize with the code by generating a few processes in QED and QCD trying to guess which diagrams appear. What is the minimum number of jets have to be asked for in %$e^+e^-$% collisions so that the triple gauge vertex appear? |
| 56 | |
| 57 | * Look at the new physics models and check the particle and interactions content. |
| 58 | |
| 59 | * Generate events for a few selected processes and look at the plots: |
| 60 | * ttbar production with decays: pp>tt~>bb~mu+e-ve~vm |
| 61 | * VV production: pp>VV> leptons, with V=Z,W. |
| 62 | * Single top + Higgs: pp>tHj (QCD=0, QED=3, j=gudsc,p=gudscb). Show that there is a large negative interference between the diagrams |
| 63 | |
| 64 | -- Main.FabioMaltoni - 05 May 2010 |
| 65 | |
| 66 | |
| 67 | |
| 68 | |
| 69 | |
| 70 | |
| 71 | |
| 72 | |
| 73 | |
| 74 | |
| 75 | |
| 76 | |
| 77 | |
| 78 | |
| 79 | |
| 80 | |
| 81 | |
| 82 | |
| 83 | |