Changes between Version 1 and Version 2 of WorkBook/Tutorials/Pisa

Timestamp:

Sep 18, 2018, 3:37:23 PM (6 years ago)

Author:

Michele Selvaggi

Comment:

--

WorkBook/Tutorials/Pisa

@@ -1 @@
-test
+[[TOC]]
+
+= MG5+Delphes Tutorial - Pisa September 2018 =
+
+== Pre-requisites ==
+
+To successfully run this tutorial the following prerequisite packages should be installed:
+
+- gcc/tcl:
+
+For linux users gcc/tcl should be already installed. For Mac users you should install XCode.
+
+- ROOT:
+
+can be downloaded from https://root.cern.ch/downloading-root
+Go on latest release, and download a version under "Binary distributions".
+
+- Pythia8:
+
+following instructions from here:
+https://cp3.irmp.ucl.ac.be/projects/delphes/wiki/WorkBook/Pythia8
+
+
+== Event generation with Pythia8 + Delphes sample ==
+
+
+This exercise will teach how to configure the Pythia8 event generator for a simple production of e+e- -> ZH events. Next, you will generate events and simulate the detector with the DelphesPythia8 executable.
+
+0) Stare at the following example "examples/Pythia8/configNoLHE.cmnd" of Pythia8 configuration file.
+In this card identify the parameters that control:
+
+- the number of events to be generated
+- the particle beam type
+- the center of mass energy
+- the physics process to be generated
+
+1) Create a Pythia8 configuration card that generates N=10k events of
+ee->Zh->mumu at sqrt(s)=240 GeV.
+
+The identifier for the above process can be found in the Pythia8 manual:
+
+http://home.thep.lu.se/~torbjorn/pythia81html/Welcome.html
+
+Hint1: the code of electron (positron) is 11 (-11).
+
+Hint2: the Z decay can be forced to muons with the following syntax:
+
+{{{
+23:onMode = off
+23:onIfAny = 13 -13
+}}}
+
+2) Produce Delphes events using the above Pythia8 configuration (this command should run Pythia and Delphes on the fly!), using the CEPC detector card "cards/delphes_card_CEPC.tcl"
+
+Hint: find the command to be executed here (adapting it to the above Delphes and Pythia8 cards of course):
+
+https://cp3.irmp.ucl.ac.be/projects/delphes/wiki/WorkBook/Pythia8
+
+
+== Simple Tree analysis ==
+
+
+1) Open Delphes ROOT tree and explore the branches
+
+{{{
+root -l delphes_ee_zh_zmumu.root
+gSystem->Load("libDelphes");
+TBrowser t;
+}}}
+
+
+Note: Most objects are described in terms of pp specific variables (PT, Eta, Phi).
+This is simply for historical reasons since Delphes was developed originally as a tool for LHC physics. To plot ee-like variables, one needs to write the translation (or make use of the very useful TLorentzVector of ROOT, see part III).
+
+2) Interactively Draw the "leading" muon pt and energy, the muon multiplicity and the jet multiplicity. Do you understand these distributions?
+
+ex:
+{{{
+Delphes->Draw("Muon[0].PT")
+}}}
+Hint: To calculate the energy approximate the muon as a massless particle and express the energy as function of pT and Eta.
+
+
+== Write a simple analysis macro ==
+
+0) Write down the formula for the recoil Higgs mass.
+
+1) You can find a simple analysis macro in "example/Example1.py". It can be executed like this:
+
+{{{
+python examples/Example1.py delphes_ee_zh_zmumu.root
+}}}
+
+This Example1.py macro does not do anything interesting for this problem (it most likely produce an empty plot). You should open it with a text editor, and write a small analysis that selects two muons and reconstructs and plot the recoil Higgs mass.
+
+
+== Modify the Delphes detector card ==
+
+
+You have now produced a Delphes simulated event with the hypothetical CEPC default detector configuration.
+
+1) Can you think of two detector parameters that drive the performance of this measurement?
+
+2) Identify where they are configured in the delphes detector card
+
+3) Create two new detector configurations by degrade these two parameters by a sizable factor.
+
+4) Reproduce a Delphes sample with these new configurations and observe the impact on the recoil mass distribution.
+
+
+