== HEPTOOLS 2008 [[br]] Graduate School in Physics at Colliders : [[br]] "From twistors to Monte Carlos" == === Lectures === Find [attachment:maltoni_lectures.pdf here] the pdf of the 4 hour lecture on "Monte Carlo's for the LHC" by Fabio Maltoni.[[br]] Find [http://www.pd.infn.it/~passera/JC_2007-08/frixione.html here] a very nice course on QCD and MC by Stefano Frixione. === MC101 === A short introduction to the techniques of Monte Carlo integration. Exercises include: * 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: [attachment:mc101.nb mc101.nb]. Reference: [http://www.slac.stanford.edu/spires/find/hep/www?eprint=hep-ph/0006269 Introduction to MC methods], by [http://wwwthep.physik.uni-mainz.de/~stefanw/ Stefan Weinzierl] === Exercises === All exercises proposed here can be "solved" or checked with MadGraph / MadEvent. To familiarize with the code click [wiki:MGFamiliarize here]. * [wiki:DeadCone Radiation from heavy quarks]: the dead cone in $e^+e^- \to Q \bar Q g$. * [wiki:GluonSpin Spin of the gluon]: Vector vs scalar in the angular correlations of $e^+ e^- \to$ 4 jets. * [wiki:2Jets Jets] : Di-jet kinematics and rates in pp collisions. * [wiki:3Jets 3 Jets] : Energy distributions in 3-jet events. * [wiki:TopDecaySpinCorrelations Spin correlations in top decay]. * [wiki:tt top production] : $t \bar t$ production, Tevatron vs LHC. * [wiki:SimpleKinematics Kinematics at the LHC]: single particle quantities. Reference: [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). === Discover the SM Higgs at the LHC === * Find the best prediction for Higgs production at the LHC [http://maltoni.web.cern.ch/maltoni/TeV4LHC/index.html here]. * Find the Higgs branching ratios [attachment:h-br.pdf here]. Choose a channel and investigate signal and background: 1. The 4 lepton final state: $pp \to H\to Z Z \to e^+e^- \mu^+ \mu^-$ * Signal * Events: [attachment:h4l-signal.lhe.gz Parton Level] [attachment:h4l-signal.lhco.gz Detector Level] {{{ #!comment }}} * Background * Events: [attachment:h4l.lhe.gz Parton Level] [attachment:h4l.lhco.gz Detector Level] {{{ #!comment }}} 1. The 2 lepton + missing Et final state: $pp \to H\to W^+ W^- \to e^- \bar \nu_e \mu^+ \nu_\mu$ * Signal * Events: [attachment:hww-signal.lhe.gz Parton Level] [attachment:hww-signal.lhco.gz Detector Level] {{{ #!comment }}} * Background * Events: [attachment:hww-background.lhe.gz Parton Level] [attachment:hww-background.lhco.gz Detector Level] {{{ #!comment }}} 1. Top associated production $pp \to t\bar tH$ with $H \to b \bar b$ * Signal + Background samples: * Events: [attachment:ttb.lhe.gz Parton Level] [attachment:ttbb.lhco.gz Detector Level] * Plots: [attachment:ttbb-lhe.pdf Parton Level] [attachment:ttbb-lhco.pdf Detector Level] === Discover New gauge bosons at the LHC === Three "black boxes" are given, in the form of event files in the LHC Olympics format and a series of selected plots: * Box A : [attachment:A.lhco.gz Events] Plots: [attachment:A-lhe.pdf Parton level] [attachment:A.pdf Detector level] * Box B : [attachment:B.lhco.gz Events] Plots: [attachment:B-lhe.pdf Parton level] [attachment:B.pdf Detector level] * Box C : [attachment:C.lhco.gz Events] Plots: [attachment:C-lhe.pdf Parton level] [attachment:C.pdf Detector level] Black boxes contain only signal events. The students are asked to pair up the boxes above with the following models and also answer to the questions: * Model 1 : Extra Z (zp) : What its mass? Does it have Standard Model couplings to fermions? * Model 2 : Heavy Scalar (h): What its mass? Is it a SM Higgs? * Model 3 : Extra W (wp+ or wp-) : What its mass? Does it have Standard Model couplings to fermions? Useful extra information: * In the plots $H_T=\sum ||p_T^{vis}|| + E_T^{miss}$. * A SM-like Z' would decay (more or less democratically) into: jet jet (uu~,cc~,dd~,ss~,bb~), t tbar (tt~), lept+lept- (e+e-,mu+mu-,ta+ta-), neutrino anti-neutrino (ve ve~,vm vm~,vt vt~). It could also have couplings to SM W and Z, and in that case would decay in to ZZ and W+W-. * An Higgs couple to particles with a strength which is proportional to the particle masses. A SM-like heavy H would decay in to t tbar (tt~), W+W-, ZZ. * A SM-like W'+ would decay into: jet jet (ud~,cs~), t b (tb~), lept neutrino (e+ ve , mu+ vm, ta+ vt). It could also have couplings to SM W and Z, and in that case would decay in to ZW. === Analysis Tools === * a Fortran-based package: MadAnalysis ([http://madgraph.phys.ucl.ac.be/cgi-bin/NewProcess/download.cgi Download it here]) * a Mathematica-based package: [http://www.jthaler.net/olympics/html Chameleon]. -- Main.FabioMaltoni - 03 Jan 2008