| 1 | |
| 2 | |
| 3 | == 2012 CERN Summer student workshop == |
| 4 | |
| 5 | === Animations === |
| 6 | * [http://madgraph.hep.uiuc.edu/Event/ Interactive Flash version] Note you may want to zoom in! |
| 7 | * [http://madgraph.hep.uiuc.edu/Event/fast_collisionx6.avi Fast movie (.avi) of collision] |
| 8 | * [http://madgraph.hep.uiuc.edu/Event/collision.mov Guided movie (.mov) of collision] |
| 9 | * [http://www.thedailyshow.com/watch/thu-april-30-2009/large-hadron-collider John Ellis on Daily Show] |
| 10 | |
| 11 | === Exercises === |
| 12 | |
| 13 | Discover the Higgs at the LHC: |
| 14 | * Find the best prediction for Higgs production at the LHC [http://maltoni.web.cern.ch/maltoni/TeV4LHC/index.html here]. |
| 15 | * Find the Higgs branching ratios [attachment:h-br.pdf here]. |
| 16 | |
| 17 | Choose a channel and investigate signal and background: |
| 18 | |
| 19 | 1. The 4 lepton final state: $pp \to H\to Z Z \to e^+e^- \mu^+ \mu^-$ |
| 20 | * Signal Plots: [attachment:h4l-signal-lhe.pdf Parton Level] [attachment:h4l-signal-lhco.pdf Detector Level] |
| 21 | * Background Plots: [attachment:h4l-lhe.pdf Parton Level] [attachment:h4l-lhco.pdf Detector Level] |
| 22 | 1. Top associated production $pp \to t\bar tH$ with $H \to b \bar b$ |
| 23 | * Signal + Background Plots: [attachment:ttbb-lhe.pdf Parton Level] [attachment:/ttbb-lhco.pdf Detector Level] |
| 24 | |
| 25 | === The Challenge === |
| 26 | |
| 27 | Three "black boxes" are given, in the form of event files in the LHC Olympics format and a series of selected plots: |
| 28 | |
| 29 | * Box A : [attachment:A.lhco.gz Events] Plots: [attachment:A-lhe.pdf Parton level] [attachment:A.pdf Detector level] |
| 30 | * Box B : [attachment:B.lhco.gz Events] Plots: [attachment:B-lhe.pdf Parton level] [attachment:B.pdf Detector level] |
| 31 | * Box C : [attachment:C.lhco.gz Events] Plots: [attachment:C-lhe.pdf Parton level] [attachment:C.pdf Detector level] |
| 32 | |
| 33 | 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: |
| 34 | |
| 35 | * Model 1 : Extra Z (zp) : What is its mass? Does it have Standard Model couplings to fermions? |
| 36 | * Model 2 : Heavy Scalar (h): What is its mass? Is it a SM Higgs? |
| 37 | * Model 3 : Extra W (wp+ or wp-) : What its mass? Does it have Standard Model couplings to fermions? |
| 38 | |
| 39 | Useful extra information: |
| 40 | * In the plots $H_T=\sum ||p_T^{vis}|| + E_T^{miss}$. |
| 41 | * 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-. |
| 42 | * 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. |
| 43 | * 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. |
| 44 | |
| 45 | * [attachment:Worksheets11.pdf Worksheets11.pdf]: Worksheets |
| 46 | |
| 47 | * [http://www.youtube.com/watch?v=j50ZssEojtM LHC_Rap] |
| 48 | |
| 49 | |