==== [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 ==== === Authors === * Rikkert Frederix (lecturer) * Claude Duhr (lecturer) === References === * [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). * [http://www.worldscibooks.com/physics/6686.html Perspectives on LHC physics, Ed. by G. Kane and A. Pierce]. * [http://home.thep.lu.se/~torbjorn/pythia/lutp0613man2.pdf Pythia 6 Physics and Manual] (excellent introduction to event generation, parton showers and hadronization). === Exercises 1: Familiarize with Software.MadGraph === * Logon to the Software.MadGraph web site and register: http://madgraph.hep.uiuc.edu. * Register with a valid e-mail address * Download the latest version of the !MadGraph v5 code from the Dowloads page on the madgraph website. * Untar it and start the command line interface by executing =./bin/mg5= * Start the tutorial by typing {{{ tutorial }}} in the mg5 command prompt and follow the instruction. Discuss the results with your neighbours. === Exercises 2: Implement a new model with FeynRules === * 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. === Extra exercises 1: On-line process generation === * Use the on-line website to generate a few processes (with different QED + QCD couplings) trying to guess which diagrams appear: * uu~>tt~ * gg>tt~ * gg>tt~h (in SM and HEFT) * uu~>tt~bb~ * Subprocess identification. List all subprocesses contributing to: * pp>l+vljj * pp>tt~bb~ * pp>tt~jj * Look at the new physics models and check the particle and interactions content. === Extra exercises 2: Calculate cross sections and generate events === * 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? * Compare cross sections with the processes of your neighbors. Do they differ as you would expect? * Look at the generated plots. Are the distributions as you would expect? Discuss with your neighbors. Example processes: * ttbar production: pp > tt~, QED=0 * W production: pp > l+vl * Z/gamma* production: pp > e+e- * g g > H, H > e+ ve mu- vm~ (in HEFT model) * p p > W+ W-, W+>e+ ve, W- > mu- vm~ (important background to previous process) === Extra exercises 3: The full simulation chain and advanced features === Try out the Analysis Tools: * a Fortran-based package: Software.MadAnalysis ([http://madgraph.phys.ucl.ac.be/cgi-bin/NewProcess/download.cgi Download it here]) * a Root-based package: Software.ExRootAnalysis ([http://madgraph.hep.uiuc.edu/cgi-bin/NewProcess/download.cgi Download it here]) Study SM Higgs production at the LHC. Choose a channel and investigate signal and background, using either of the packages above: 1. The 2 lepton + missing Et final state: $ pp \to H\to W^+ W^- \to e^- \bar \nu_e \mu^+ \nu_\mu $ 1. * Signal * 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] * 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] * Background * Events: [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/DiscoverTheHiggs/hww-background.lhe.gz Parton Level] || [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/DiscoverTheHiggs/hww-background.lhco.gz Detector Level] * Plots: [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/DiscoverTheHiggs/hww-background-lhe.pdf Parton Level] || [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/DiscoverTheHiggs/hww-background-lhco.pdf Detector Level] 1. Top associated production $pp \to t\bar tH$ with $H \to b \bar b$ * Signal + Background samples: * 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] * 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] === Extra exercises 4: Implementation of a new model in !MadGraph or [http://feynrules.phys.ucl.ac.be/ FeynRules] + !MadGraph === * Implement your favourite Model into !MadGraph using FeynRules, specific for studying a given process. Generate events, study relevant distributions. * Determine most relevant Standard Model backgrounds with identical final states (“non-reducible”). If not too complicated, generate backgrounds with cuts determined from signal distributions. * Which other (“reducible”) backgrounds might be important? * Can the signal be seen at Tevatron? At the LHC? ==== Animations ==== * [http://madgraph.hep.uiuc.edu/Event/ Interactive Flash version] Note you may want to zoom in! * [http://madgraph.hep.uiuc.edu/Event/fast_collisionx6.avi Fast movie (.avi) of collision] * [http://madgraph.hep.uiuc.edu/Event/collision.mov Guided movie (.mov) of collision] * [http://www.thedailyshow.com/watch/thu-april-30-2009/large-hadron-collider John Ellis on Daily Show]