2007 CERN Summer student workshop

Exercises

Discover the Higgs at the LHC:

Find the best prediction for Higgs production at the LHC ​here. Find the Higgs branching ratios here​.

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

Events: Parton Level​ Detector Level​ Plots: Parton Level​ Detector Level​

Background

Events: Parton Level​ Detector Level​ Plots: Parton Level​ Detector Level​

The 2 lepton + missing Et final state: $pp \to H\to W^{+ W}- \to e^{- \bar \nu_e \mu}+ \nu_\mu $

Signal

Events: Parton Level​ Detector Level​ Plots: Parton Level​ Detector Level​

Background

Events: Parton Level​ Detector Level Plots: Parton Level Detector Level

Top associated production $pp \to t\bar tH$ with $H \to b \bar b$

Signal + Background samples:

Events: Parton Level​ Detector Level​ Plots: Parton Level​ Detector Level​

The Challenge

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

Box A : Events​ Plots: Parton level​ Detector level​ Box B : Events​ Plots: Parton level​ Detector level​ Box C : Events​ Plots: Parton lelve​ 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.

-- Main.FabioMaltoni - 08 Aug 2007

2012 CERN Summer student workshop

Exercises

Discover the Higgs at the LHC:

Find the best prediction for Higgs production at the LHC ​here. Find the Higgs branching ratios here​.

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

Events

Parton Level​ Detector Level​

Plots

Parton Level​ Detector Level​ Background

Events

Parton Level​ Detector Level​

Plots: Parton Level​ Detector Level​ The 2 lepton + missing Et final state

$pp \to H\to W^{+ W}- \to e^{- \bar \nu_e \mu}+ \nu_\mu $ Signal

Events

Parton Level​ Detector Level​

Plots

Parton Level​ Detector Level​ Background

Events

Parton Level​ Detector Level

Plots

Parton Level Detector Level Top associated production $pp \to t\bar tH$ with $H \to b \bar b$ Signal + Background samples:

Events

Parton Level​ Detector Level​

Plots

Parton Level​ Detector Level​

The Challenge

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

Box A : Events​ Plots: Parton level​ Detector level​ Box B : Events​ Plots: Parton level​ Detector level​ Box C : Events​ Plots: Parton lelve​ 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.

-- Main.FabioMaltoni - 08 Aug 2007 -- Main.FabioMaltoni - 2011-07-12