delphes_EIC

Welcome to the delphes_EIC project. This code aims to deliver a fast-simulation model of baseline or specific detectors for studies to support the Electron-Ion Collider (EIC) project. This code has been used in a few publications and papers and parts of it are available for citation through Zenodo:

• Charm jets as a probe for strangeness at the future Electron-Ion Collider. Miguel Arratia (UC, Riverside and Jefferson Lab), Yulia Furletova (Jefferson Lab), T.J. Hobbs (Southern Methodist U. and Jefferson Lab), Fredrick Olness (Southern Methodist U.), Stephen J. Sekula (Southern Methodist U.). e-Print: 2006.12520[hep-ph]
• A Delphes card for the EIC yellow-report detector. Miguel Arratia (UC, Riverside and Jefferson Lab), Stephen Sekula (Southern Methodist U.). e-Print: 2103.06886[physics.ins-det]. DOI: 10.5281/zenodo.4592887(publication)
• Science Requirements and Detector Concepts for the Electron-Ion Collider: EIC Yellow Report. R. Abdul Khalek, A. Accardi, J. Adam, D. Adamiak, W. Akers et al. e-Print: 2103.05419 [physics.ins-det]

New!

• EIC PID code has been used to create IdentificationMaps for the mRICH, barrelDIRC, and dualRICH. No more external code needed!

Instructions

1. Install PYTHIA8.3 following the instructions below, because code-patching is necessary to fix a bug in the DIS simulation.

2. Install Delphes3 following: https://github.com/delphes/delphes

EIC Yellow-Report Detector Models

The current model we recommend is delphes_card_allsilicon_3T.tcl, which is based on detector studies from the EIC Yellow Report (https://arxiv.org/abs/2103.05419). This model incorporates all-silicon tracking, and EMCAL and HCAL. PID system responses are provided by efficiency maps based on EIC PID code (https://gitlab.com/preghenella/pid/).

• Magnetic field: 3.0 T
• Solenoid length: 2.0 m
• Tracker radius: 80 cm

We currently simulte DIS using Pythia8 within Delphes. Again, detailed instructions for patching and installing it are below. The command file (ending in .cmnd) shown here is suitable for DIS at EIC.

Generating Events

Run generation command: ./DelphesPythia8 cards/delphes_card_allsilicon_3T.tcl CC_DIS.cmnd out.root

You can see examples of analysis code in the Delphes page above

Visualizing Events

Run visualization command: root -l examples/EventDisplay.C'("delphes_card_allsilicon_3T.tcl","out.root")'

The two examples shown here are for neutral-current and charged-current event for beam energies of 10 GeV electron on 100 GeV proton (63 GeV center-of-mass energy).

Code Installation

Below, the environment variable ${INSTALLDIR} refers to some folder where you are putting all your EIC fast simulation code (e.g. export INSTALLDIR=${HOME}/EIC/).

1. Install LHAPDF
   • https://lhapdf.hepforge.org/
   • Using LHAPDF 6.2.3
   • Download the tarball and unpack it
   • BUGFIX in 6.2.3: there is a python coding error in bin/lhapdf. Edit this file and find and replace "add_add_mutually_exclusive_group" with "add_mutually_exclusive_group"
   • Configure it for local installation in your work area, e.g. ./configure --prefix=${INSTALLDIR}/EIC/
   • Build it, make -j,
   • Install it, make install,
   • Make sure the environment is set properly to find the binaries, libraries, and python code (c.f. https://lhapdf.hepforge.org/install.html#lxplus for examples)
2. Install PYTHIA8,
   • http://home.thep.lu.se/~torbjorn/Pythia.html,
   • Download the tarball and unpack it. ,
   • Patch Pythia8: There is a known BUG in Pythia8.X that affects deep-inelastic scattering (DIS) simulations. To fix this, you need to follow the instructions below on "Patching Pythia8 for DIS". DO THIS NOW
   • Configure it for local installation in your work area, e.g. ./configure --prefix=${INSTALLDIR}/EIC/ --with-lhapdf6=/scratch${INSTALLDIR}/EIC/,
   • Build it, make -j,
   • Install it, make install,
   • Make sure the work area binary directory is in your PATH: PATH=${INSTALLDIR}/EIC/bin:${PATH},
3. Install Delphes,
   • https://github.com/delphes/delphes,
   • Clone the project and make sure you are on the master branch,
   • Make sure ROOT is available in your path, e.g. lsetup \"root 6.18.04-x86_64-centos7-gcc8-opt\",
   • Set environment variables for building: export HAS_PYTHIA8=true; export PYTHIA8=${INSTALLDIR}/EIC
   • Configure: ./configure --prefix=${INSTALLDIR}/EIC/,
   • Build: make -j,
   • Install: make install,

Patching Pythia8 for DIS

• Edit the following file in your Pythia8 source directory: src/BeamRemnants.cc
• Go to the BeamRemnants::setOneRemnKinematics method (it will begin around line 960 or so)
• Find the lines that look as follows:

int iLepScat = isDIS ? (beamOther[0].iPos() + 2) : -1;

• Add the following lines just below this code:

if (iLepScat > (event.size()-1)) {
   // Occasionally, the remnant is missing from the record.
   // Return false 
   return false;
 }

Now compile the Pythia8 code. This will fix the bug.

Running Monte Carlo Production

The following command line will run these options:

• e-p beam energies of 10 and 275, respectively
• LHAPDF6:CT18NNLO PDF set
• Output will be written to CC_DIS_e10_p275_CT18NNLO/0/ (where 0 is the task ID, specified using SLURM_ARRAY_TASK_ID)
• 100,000 events generated in a single run of the command

SLURM_ARRAY_TASK_ID=0 ./run_study.py --template delphes_card_allsilicon_3T.tcl --commands CC_DIS_template.cmnd -p '{"PARAM_NEVENTS": 100000, "PARAM_HADBEAM_ENERGY": 275, "PARAM_EBEAM_ENERGY": 10, "PARAM_PDFSET": "LHAPDF6:CT18NNLO"}' -n CC_DIS_e10_p275_CT18NNLO

EIC Collider Variations

Beam energy recommended benchmarking points are (the order is hadron on lepton):

• 275 on 18 GeV
• 100 on 10 GeV
• 100 on 5 GeV
• 41 on 5 GeV

The "SimpleAnalysis" framework

See the dedicated SimpleAnalysis Code Design README file.