| | 1 | = 2015 CERN Summer student workshop = |
| | 2 | |
| | 3 | |
| | 4 | == Exercises : discover the Higgs boson at the LHC == |
| | 5 | |
| | 6 | * Find predictions for Higgs boson production at the LHC [http://maltoni.web.cern.ch/maltoni/TeV4LHC/index.html here]. |
| | 7 | * Find the Higgs boson branching ratio table [attachment:h-br.pdf here]. |
| | 8 | * Choose a channel and investigate both the signal and background: |
| | 9 | 1. The 4 lepton final state: $pp \to H\to Z Z \to e^+e^- \mu^+ \mu^-$ |
| | 10 | * Signal Plots: [attachment:h4l-signal-lhe.pdf Parton Level] [attachment:h4l-signal-lhco.pdf Detector Level] |
| | 11 | * Background Plots: [attachment:h4l-bgd-lhe.pdf Parton Level] [attachment:h4l-bgd-lhco.pdf Detector Level] |
| | 12 | 2. Top associated production $pp \to t\bar tH$ with $H \to b \bar b$ |
| | 13 | * Signal + Background Plots: [attachment:ttbb-lhe.pdf Parton Level] [attachment:ttbb-lhco.pdf Detector Level] |
| | 14 | |
| | 15 | |
| | 16 | == The Challenge == |
| | 17 | |
| | 18 | Three "black boxes" are given, in the form of event files in the LHC Olympics (LHCO) format and a series of selected figures. |
| | 19 | * Box A : [attachment:A-events.lhco.gz Events], [attachment:A-partonfigs.pdf parton level figures], [attachment:A-recofigs.pdf detector level figures] |
| | 20 | * Box B : [attachment:B-events.lhco.gz Events], [attachment:B-partonfigs.pdf parton level figures], [attachment:B-recofigs.pdf detector level figures] |
| | 21 | * Box C : [attachment:C-events.lhco.gz Events], [attachment:C-partonfigs.pdf parton level figures], [attachment:C-recofigs.pdf detector level figures] |
| | 22 | |
| | 23 | These Black boxes are associated with signal events only. It is asked to pair up the boxes above with the three following new physics models and answer the related questions: |
| | 24 | * Model 1 - Extra neutral gauge boson (Z'): what is its mass and does it have Standard Model couplings to fermions? |
| | 25 | * Model 2 - Heavy scalar (heavy Higgs boson): what is its mass and is it a Standard Model Higgs boson? |
| | 26 | * Model 3 - Extra charged gauge boson (W'): what its mass and does it have Standard Model couplings to fermions? |
| | 27 | |
| | 28 | To solve these exercises, useful extra information can be found below: |
| | 29 | * In the figures, $H_T=\sum ||p_T^{vis}|| + E_T^{miss}$. |
| | 30 | * A Z' boson with Standard Model couplings would decay (more or less democratically) into: jet jet (uu~,cc~,dd~,ss~,bb~), t tbar (tt~), l+l- (e+e-,mu+mu-,ta+ta-), neutrino anti-neutrino (ve ve~,vm vm~,vt vt~). It could also have couplings to the Standard Model W and Z bosons, and in that case would decay in to ZZ and W+W-. |
| | 31 | * A Higgs boson couples to particles with a strength which is proportional to the particle masses. A Standard Model-like heavy Higgs boson would decay in to t tbar (tt~), W+W- and ZZ. |
| | 32 | * A W' boson with Standard Model-like couplings would decay into: jet jet (ud~,cs~), t b (tb~), lepton-neutrino (e+ ve , mu+ vm, ta+ vt). It could also have couplings to the Standard Model W and Z bosons, and in that case would decay in to ZW. |
| | 33 | |
| | 34 | |
| | 35 | == Animations == |
| | 36 | * [http://madgraph.hep.uiuc.edu/Event/ Interactive Flash version] Note you may want to zoom in! |
| | 37 | * [http://madgraph.hep.uiuc.edu/Event/fast_collisionx6.avi Fast movie (.avi) of collision] |
| | 38 | * [http://madgraph.hep.uiuc.edu/Event/collision.mov Guided movie (.mov) of collision] |
| | 39 | * [http://www.youtube.com/watch?v=j50ZssEojtM LHC_Rap] |
| | 40 | |
| | 41 | == Slides == |
| | 42 | * [attachment:mg5_CERN_SummerStudents2015.pdf Download here] |
