CernSummerSchool09 – MadGraph

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Version 1 (modified by trac, 13 years ago) ( diff )
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Discover the Higgs at the LHC:

Choose a channel and investigate signal and background:

The 4 lepton final state: %$pp \to H\to Z Z \to e^+e- \mu^{+ \mu}-$%
- Signal Plots: Parton Level Detector Level
- Background Plots: Parton Level Detector Level
Top associated production %$pp \to t\bar tH$% with %$H \to b \bar b$%
- Signal + Background Plots: Parton Level Detector Level

Three "black boxes" are given, in the form of event files in the LHC Olympics format and a series of selected plots:

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.