This tutorial is intended to provide you with the basic you need in order to deal with jets in your analysis. We start with the basics of what is a jet, how are they reconstructed, what algorithms are used, etc. Then we give examples with scripts on how to access jets and use them in your analysis frameworks, including corrections and systematics. In the second part of the exercise, we examine jet substructure algorithms, which have many uses including identification of hadronic decays of heavy SM particles like top quarks, W, Z, and H bosons, as well as mitigation of pileup and others.
This tutorial is designed to be executed as notebooks in SWAN. Also script based versions of the exercises are provided, which can be executed in lxplus.
- Ashley Parker
- Andris Potrebko
- Mikael Myllymäki
Jets & jet substructure short exercise channel
This version of the same tutorial uses Jupyer Notebooks as a browser-based development environment at CERN-SWAN the content of these notebooks is the same as the one in lxplus, it is just a different set up.
Go to https://swan.cern.ch and log in with your CERN account. After that you need to configure your environment, please use these settings:
The most important configuration is the software stack, which has to be 97a Python2. After that click on start the session.
Once you are in My Projects, create a new project by clicking on the plus icon on the right part of My Projects. Enter the project name you like, for this example we will use CMSDAS_jetExercise.
Open up a terminal by clicking on the icon:
Once there, you are in your cernbox home area, and you can follow these steps:
cd SWAN_projects/CMSDAS_jetExercise/
wget https://raw.githubusercontent.com/cms-jet/JMEDAS/DASJan2022/setup-libraries_SWAN.sh
source setup-libraries_SWAN.sh
This will take a while, but basically you are setting your CMSSW environment, cloning some packages, and creating the kernel used in this exercises. If the compilation is succesful, you should see something similar to this at the end of the messages:
Loaded CMSSW_10_6_6 into hats-jec!
After this you can go to ~/CMSDAS_jetExercise/DAS/ and continue with the tutorial.
The previous steps you have to do it once. Additionally, two important things:
-You need to follow the instructions below to set your grid certificate.
-If you try to access any of the notebooks any other day, it will require you to confirm the kernel. For that please select the hats-jec option.
To access data stored remotely in different places, you need to set your grid certificate.
- *For runing on lxplus, you only need to run (to get a valid certificate):
voms-proxy-init -voms cms -valid 192:00- SWAN still does not have a simple way of setting this certificate internally, but we can use a workaround. First, open a "normal" connection to lxplus/cmslpc from your computer (NOT from the SWAN command line), execute
voms-proxy-init -voms cms -valid 192:00and look at the prints. Your certificate is located in a file with a name like this:/tmp/x509up_u00000(lxplus)~/x509up_u00000(cmslpc) (with some other numbers instead of 0000). If the location is not printed out (on cmslpc), you can runecho $X509_USER_PROXYto find the location. Copy it to your cernbox area like this:
cp /tmp/x509up_u0000 /eos/home-X/Y/ ### (on lxplus) where X is the first letter of your cern user id, and Y is your cern user id. `~/x509up_u0000` has to be replaced to the location of the created proxy.
#scp $X509_USER_PROXY Y@lxplus.cern.ch:/eos/home-X/Y/ ### (from cmslpc) where X is the first letter of your cern user id, and Y is your cern user id. `~/x509up_u0000` has to be replaced to the location of the created proxy.Now you are ready to activate your certificate in jupyter notebooks in SWAN by first changing the second line of the cell with the location of your certificate file, and then running (i.e. clicking 'play' in) a cell that looks like this:
import os
os.environ['X509_USER_PROXY'] = '{}/x509up_00000'.format(os.environ["HOME"]) ### remember to change this line with what you did above
if os.path.isfile(os.environ['X509_USER_PROXY']):
print("Found proxy at {}".format(os.environ['X509_USER_PROXY']))
else:
print("Failed to find proxy at {}".format(os.environ['X509_USER_PROXY']))
os.environ['X509_CERT_DIR'] = '/cvmfs/cms.cern.ch/grid/etc/grid-security/certificates'
os.environ['X509_VOMS_DIR'] = '/cvmfs/cms.cern.ch/grid/etc/grid-security/vomsdir'The cell should be present in every exercise where you need the authentication. REMEMBER to do this every day that you will try to access remote files in SWAN.
Once you've completed the setup instructions, change to the directory ~/SWAN_projects/CMSDAS_jetExercise/DAS/ in SWAN. Information on the separate tutorial can be found in the "notebooks" subdirectory.
Open a terminal/console, connect to lxplus and prepare your working area (instructions are in bash shell syntax):
ssh -Y <username>@lxplus.cern.ch
mkdir JMEDAS2023
cd JMEDAS2023
export SCRAM_ARCH=slc7_amd64_gcc700
source /cvmfs/cms.cern.ch/cmsset_default.sh
scramv1 -n CMSSW10618_JMEDAS CMSSW_10_6_18 ### choose an appropriate directory name instead of `CMSSW10618_JMEDAS`
cd CMSSW10618_JMEDAS/src
cmsenv
git clone https://github.com/AndrissP/JMEDAS.git Analysis/JMEDAS
git clone https://github.com/cms-jet/JetToolbox Analysis/JetToolbox -b jetToolbox_102X_v3
cd Analysis/JMEDAS
scram b -j 4
In some exercises we also need to access files in remote servers, so activate your grid certificate:
voms-proxy-init -voms cms -valid 192:00
Optional. If you like seeing your working directory in the commandline, you can do also this by adding a line to ~/.bashrc and activating it with the 'source' command:
echo "PS1='\W\$ '" >> ~/.bashrc
source ~/.bashrc
Now, you can start with the basics.py script in Section 1.
- JERC Subgroup Twiki Page
- The new run 3 JERC subgroup webpage
- JetMET/JERC/JMAR Weekly Meetings
- Run2 Weekly Discussion Group
- Every other week there is a meeting on jets and pileup
- SQLite files, text files, and tarballs
- JetToolbox Twiki Page
- 2017 MiniAOD Twiki Page