Changes between Initial Version and Version 1 of WorkBook/Tutorials/Hefei

Timestamp:

Nov 20, 2018, 11:08:25 AM (6 years ago)

Author:

Michele Selvaggi

Comment:

--

WorkBook/Tutorials/Hefei

@@ +1 @@
+[[TOC]]
+
+= Pythia8+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 (or using the Pythia8 installation in MadGraph):
+https://cp3.irmp.ucl.ac.be/projects/delphes/wiki/WorkBook/Pythia8
+
+== I) 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.
+
+1)  First have a look at the Pythia8 configuration file "examples/Pythia8/configNoLHE.cmnd".
+In this card identify the parameters that control:
+
+- the number of events to be generated
+- the nature of the colliding beams
+- the center of mass energy
+- the physics process to be generated
+
+2) Create a Pythia8 configuration card that generates N=10k events of ee->Zh->mumu at sqrt(s)=240 GeV.
+
+Find the above process in the Pythia8 manual (Hint: under "Higgs", then "Standard-Model Higgs, basic processes"):
+
+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
+}}}
+
+3) 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
+
+
+== II) 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 (and makes of course no difference whatsoever) 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 muon multiplicity and the jet multiplicity. Do you understand these distributions?
+
+== III) Write a simple analysis macro ==
+
+1) Write down the formula for the recoil Higgs mass.
+
+2) 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 produce anything interesting here (it most likely produce an empty plot). The above command is simply shown as an example for how to run a macro. You should open Example1.py with a text editor, and write a small analysis that first selects events with two muons and then reconstructs and plot the recoil Higgs mass using the formula found in III.1)
+
+
+== IV) 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 2 detector parameters that determine and drive the sensitivity of the Higgs recoil measurement in this particular final state?
+
+2) Identify where they are configured in the delphes detector card.
+
+3) Create two new detector configurations by degrading 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.
+
+
+