| | 1 | |
| | 2 | |
| | 3 | ==== [http://www.hep.phy.cam.ac.uk/theory/mcschool11/ 2011 IPMU-YITP on Monte Carlo Tools for the LHC], Yukawa Institute for Theoretical Physics, Kyoto, 5-10 Sep 2011 ==== |
| | 4 | |
| | 5 | === Authors === |
| | 6 | |
| | 7 | * Rikkert Frederix (lecturer) |
| | 8 | * Claude Duhr (lecturer) |
| | 9 | |
| | 10 | === References === |
| | 11 | |
| | 12 | * [http://www.hep.phy.cam.ac.uk/theory/webber/QCDbook.html QCD and Collider Physics] by Keith Ellis, James Stirling, Bryan Webber (Cambridge Monographs, 1996). |
| | 13 | * [http://www.worldscibooks.com/physics/6686.html Perspectives on LHC physics, Ed. by G. Kane and A. Pierce]. |
| | 14 | * [http://home.thep.lu.se/~torbjorn/pythia/lutp0613man2.pdf Pythia 6 Physics and Manual] (excellent introduction to event generation, parton showers and hadronization). |
| | 15 | |
| | 16 | === Exercises 1: Familiarize with Software.MadGraph === |
| | 17 | |
| | 18 | * Logon to the Software.MadGraph web site and register: http://madgraph.hep.uiuc.edu. |
| | 19 | * Register with a valid e-mail address |
| | 20 | * Download the latest version of the !MadGraph v5 code from the Dowloads page on the madgraph website. |
| | 21 | * Untar it and start the command line interface by executing =./bin/mg5= |
| | 22 | * Start the tutorial by typing {{{tutorial}}} in the mg5 command prompt and follow the instruction. Discuss the results with your neighbours. |
| | 23 | |
| | 24 | === Exercises 2: Implement a new model with FeynRules === |
| | 25 | * Read the tutorial sheet [attachment:Tutorial.pdf Tutorial.pdf] and follow the instructions together with your neighbours. If you don't have Mathematica, you can download the model files [attachment:Triplet_Top.tgz here] and jump directly to corresponding section of the tutorial sheet. |
| | 26 | |
| | 27 | === Extra exercises 1: On-line process generation === |
| | 28 | * Use the on-line website to generate a few processes (with different QED + QCD couplings) trying to guess which diagrams appear: |
| | 29 | * uu~>tt~ |
| | 30 | * gg>tt~ |
| | 31 | * gg>tt~h (in SM and HEFT) |
| | 32 | * uu~>tt~bb~ |
| | 33 | * Subprocess identification. List all subprocesses contributing to: |
| | 34 | * pp>l+vljj |
| | 35 | * pp>tt~bb~ |
| | 36 | * pp>tt~jj |
| | 37 | * Look at the new physics models and check the particle and interactions content. |
| | 38 | |
| | 39 | === Extra exercises 2: Calculate cross sections and generate events === |
| | 40 | * Generate events for a few selected processes (work in groups, pick one each), for Tevatron and LHC energies. Does the cross section scale as you expect? |
| | 41 | * Compare cross sections with the processes of your neighbors. Do they differ as you would expect? |
| | 42 | * Look at the generated plots. Are the distributions as you would expect? Discuss with your neighbors. |
| | 43 | |
| | 44 | Example processes: |
| | 45 | * ttbar production: pp > tt~, QED=0 |
| | 46 | * W production: pp > l+vl |
| | 47 | * Z/gamma* production: pp > e+e- |
| | 48 | * g g > H, H > e+ ve mu- vm~ (in HEFT model) |
| | 49 | * p p > W+ W-, W+>e+ ve, W- > mu- vm~ (important background to previous process) |
| | 50 | |
| | 51 | === Extra exercises 3: The full simulation chain and advanced features === |
| | 52 | |
| | 53 | Try out the Analysis Tools: |
| | 54 | * a Fortran-based package: Software.MadAnalysis ([http://madgraph.phys.ucl.ac.be/cgi-bin/NewProcess/download.cgi Download it here]) |
| | 55 | * a Root-based package: Software.ExRootAnalysis ([http://madgraph.hep.uiuc.edu/cgi-bin/NewProcess/download.cgi Download it here]) |
| | 56 | |
| | 57 | Study SM Higgs production at the LHC. Choose a channel and investigate signal and background, using either of the packages above: |
| | 58 | 1. The 2 lepton + missing Et final state: %$ pp \to H\to W^+ W^- \to e^- \bar \nu_e \mu^+ \nu_\mu $% |
| | 59 | 1. |
| | 60 | * Signal |
| | 61 | * Events: [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/DiscoverTheHiggs/hww-signal.lhe.gz Parton Level] || [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/DiscoverTheHiggs/hww-signal.lhco.gz Detector Level] |
| | 62 | * Plots: [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/DiscoverTheHiggs/hww-signal-lhe.pdf Parton Level] || [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/DiscoverTheHiggs/hww-signal-lhco.pdf Detector Level] |
| | 63 | * Background |
| | 64 | * Events: [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/DiscoverTheHiggs/hww-background.lhe.gz Parton Level] <span style="color: #000000;">|| </span>[http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/DiscoverTheHiggs/hww-background.lhco.gz Detector Level] |
| | 65 | * Plots: [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/DiscoverTheHiggs/hww-background-lhe.pdf Parton Level] <span style="color: #000000;">|| </span>[http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/DiscoverTheHiggs/hww-background-lhco.pdf Detector Level] |
| | 66 | 1. Top associated production %$pp \to t\bar tH$% with %$H \to b \bar b$% |
| | 67 | * Signal + Background samples: |
| | 68 | * Events: [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/DiscoverTheHiggs/ttbb.lhe.gz Parton Level] || [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/DiscoverTheHiggs/ttbb.lhco.gz Detector Level] |
| | 69 | * Plots: [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/DiscoverTheHiggs/ttbb-lhe.pdf Parton Level] || [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/DiscoverTheHiggs/ttbb-lhco.pdf Detector Level] |
| | 70 | |
| | 71 | === Extra exercises 4: Implementation of a new model in !MadGraph or [http://feynrules.phys.ucl.ac.be/ FeynRules] + !MadGraph === |
| | 72 | * Implement your favourite Model into !MadGraph using FeynRules, specific for studying a given process. Generate events, study relevant distributions. |
| | 73 | * Determine most relevant Standard Model backgrounds with identical final states (“non-reducible”). If not too complicated, generate backgrounds with cuts determined from signal distributions. |
| | 74 | * Which other (“reducible”) backgrounds might be important? |
| | 75 | * Can the signal be seen at Tevatron? At the LHC? |
| | 76 | |
| | 77 | ==== Animations ==== |
| | 78 | * [http://madgraph.hep.uiuc.edu/Event/ Interactive Flash version] Note you may want to zoom in! |
| | 79 | * [http://madgraph.hep.uiuc.edu/Event/fast_collisionx6.avi Fast movie (.avi) of collision] |
| | 80 | * [http://madgraph.hep.uiuc.edu/Event/collision.mov Guided movie (.mov) of collision] |
| | 81 | * [http://www.thedailyshow.com/watch/thu-april-30-2009/large-hadron-collider John Ellis on Daily Show] |
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