Changes between Version 9 and Version 10 of SchoolIndia


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Timestamp:
12/01/11 19:00:16 (8 years ago)
Author:
omatt
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  • SchoolIndia

    v9 v10  
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     31 = LHC Phenomenology with MadGraph =
     32
     33
     34 == Lectures ==
     35Find the pdf of the 7 x 1.5 hours lecture:(available after lectures)
     36   * General lectures on MC's (mornings) : [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/Copenhagen2010/lectures-NBI.pdf here].
     37   * MadGraph tutorials (afternoons) : [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/Copenhagen2010/tutorials-NBI.pdf here].
     38 == References ==
     39
     40   * [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).
     41   * [http://cp3wks05.fynu.ucl.ac.be/twiki/bin/view/Physics/FurtherReading Perspectives on LHC physics, Ed. by G. Kane and A. Pierce].
    3142 
     43== MadGraph and Pheno Exercises ==
     44A summary of advanced QCD and pheno exercises can be found [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/Copenhagen2010/exercises-NBI.pdf here].
     45 === Tutorial 1: Familiarize with MadGraph ===
     46   * Logon to the MadGraph web site and register: http://madgraph.hep.uiuc.edu.
     47   * Register with a valid e-mail address
     48   * Feynman diagrams. Generate a few processes (with different QED + QCD couplings) trying to guess which diagrams appear:
     49      * uu~>tt~
     50      * gg>tt~
     51      * gg>tt~h
     52      * uu~>tt~bb~
     53   * Subprocess identification. List all subprocesses contributing to:
     54      * pp>h>tt~bb~
     55      * pp>tt~bb~
     56      * pp>tt~jj
     57   * Look at the new physics models and check the particle and interactions content.
     58   * Advanced: Download the MG/ME package and play with the standalone version.
     59   * [http://cp3wks05.fynu.ucl.ac.be/twiki/bin/view/Physics/SimpleKinematics Kinematics at the LHC]: refresh the kinematics of an hadron collider.
     60 === Tutorial 2: Calculate cross sections and generate events ===
     61
     62Generate events for a few selected processes and look at the plots:
     63
     64   * ttbar production with decays: p p > t t~, t > b mu+ vm , t~ > b~ e- ve~
     65   * VV production: pp>VV> leptons, with V=Z,W.
     66   * Single top + Higgs: pp>tHj (QCD=0, QED=3, j=gudsc,p=gudscb). Show that there is a large negative interference between the diagrams.
     67   * gg>H>WW
     68   * Weak boson fusion
     69
     70Some phenomenological applications (at the parton level):
     71
     72   * [http://cp3wks05.fynu.ucl.ac.be/twiki/bin/view/Physics/2Jets Jets] : Di-jet kinematics and rates in pp collisions.
     73   * [http://cp3wks05.fynu.ucl.ac.be/twiki/bin/view/Physics/3Jets 3 Jets] : Energy distributions in 3-jet events.
     74   * [http://cp3wks05.fynu.ucl.ac.be/twiki/bin/view/Physics/WAsymm Drell-Yan] : Study the rapidity asymmetry at the Tevatron.
     75   * [http://cp3wks05.fynu.ucl.ac.be/twiki/bin/view/Physics/tt top production] : $t \bar t$ production, Tevatron vs LHC.
     76   * [http://cp3wks05.fynu.ucl.ac.be/twiki/bin/view/Physics/tprime t' production] : $t'$ production at the LHC.
     77 === Tutorial 3: The full simulation chain and advanced features ===
     78
     79Try out the Analysis Tools:
     80   * a Fortran-based package: MadAnalysis ([http://madgraph.phys.ucl.ac.be/cgi-bin/NewProcess/download.cgi Download it here])
     81
     82Study what is known of a SM Higgs at the LHC:
     83   * Find the best prediction for Higgs production at the LHC [http://maltoni.web.cern.ch/maltoni/TeV4LHC/index.html here].
     84   * Find the Higgs branching ratios [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/CernSummerSchool08/h-br.pdf here].
     85Choose a channel and investigate signal and background:
     86   1. The 2 lepton + missing Et final state: $pp \to H\to W^+ W^- \to e^- \bar \nu_e \mu^+ \nu_\mu$
     87      * Signal
     88         * 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]
     89         * 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]
     90      * Background
     91         * 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]
     92         * 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]
     93   2. Top associated production $pp \to t\bar tH$ with $H \to b \bar b$
     94      * Signal + Background samples:
     95         * 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]
     96         * 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]
     97
     98 === Tutorial 4: The MadGraph BlackBox Challenge ===
     99
     100Three "black boxes" are given, in the form of event files in the LHC Olympics format and a series of selected plots:
     101
     102   * Box A : [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/Milano2010/A.lhco.gz Events] Plots: [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/Milano2010/A-lhe.pdf Parton level] [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/Milano2010/A.pdf Detector level]
     103   * Box B : [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/Milano2010/B.lhco.gz Events] Plots: [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/Milano2010/B-lhe.pdf Parton level] [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/Milano2010/B.pdf Detector level]
     104   * Box C : [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/Milano2010/C.lhco.gz Events] Plots: [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/Milano2010/C-lhe.pdf Parton level] [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/Milano2010/C.pdf Detector level]
     105
     106Black 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:
     107
     108   * Model 1 : Extra Z (zp) : What its mass? Does it have Standard Model couplings to fermions?
     109   * Model 2 : Heavy Scalar (h): What its mass? Is it a SM Higgs?
     110   * Model 3 : Extra W (wp+ or wp-) : What its mass? Does it have Standard Model couplings to fermions?
     111
     112Useful extra information:
     113   * In the plots $H_T=\sum |p_T^{vis}| + E_T^{miss}$.
     114   * 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-.
     115   * 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.
     116   * 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.
     117
     118 === Monte Carlo's ===
     119
     120For those interested in getting deeper into Monte Carlo techniques, here are some more exercises:
     121
     122   * Write the simplest integration function based on the definition of average and error
     123   * Importance sampling via an analytic transformation
     124   * Von Neumann's rejection method : plain and improved
     125   * Phase space for 1 -> n particles
     126   * Vegas
     127   * Top decay : comparison among the various methods
     128   * qq -> tt production
     129
     130All exercises are presented and solved this Mathematica Notebook: [http://cp3wks05.fynu.ucl.ac.be/twiki/pub/Physics/Copenhagen2010//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]
     131 === Animations ===
     132   * [http://madgraph.hep.uiuc.edu/Event/ Interactive Flash version] Note you may want to zoom in!
     133   * [http://madgraph.hep.uiuc.edu/Event/fast_collisionx6.avi Fast movie (.avi) of collision]
     134   * [http://madgraph.hep.uiuc.edu/Event/collision.mov Guided movie (.mov) of collision]
     135   * [http://www.thedailyshow.com/watch/thu-april-30-2009/large-hadron-collider John Ellis on Daily Show]
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