[Paper Review] A Delphes card for the EIC yellow-report detector

M. Arratia, S. J. Sekula|arXiv (Cornell University)|Mar 10, 2021

Particle physics theoretical and experimental studies4 references4 citations

TL;DR

This paper presents a Delphes detector card implementing the Electron-Ion Collider (EIC) Yellow Report's design specifications for a 1.5 T and 3.0 T solenoidal field, enabling fast simulation of detector responses for electron-proton collisions. It demonstrates performance in jet resolution, missing transverse energy, charm tagging, and particle identification using Pythia 8, providing a validated, updatable framework to accelerate EIC physics studies with minimal computational cost.

ABSTRACT

The Electron-Ion Collider (EIC) Yellow Report specified parameters for the general-purpose detector that can deliver the scientific goals delineated by the EIC White Paper and NAS report. These parameters dictate the tracking momentum resolution, secondary-vertex resolutions, calorimeter energy resolutions, as well as $π/K/p$ ID. We have incorporated these parameters into a configuration card for Delphes, which is a widely used "C++ framework, for performing a fast multipurpose detector response simulation". We include both the 1.5 T and 3.0 T scenarios. We also show the expected performance for high-level quantities such as jets, missing transverse energy, charm tagging, and others. These parametrizations can be easily updated with more refined Geant4 studies, which provides an efficient way to perform simulations to benchmark a variety of observables using state-of-the art event generators such as Pythia8.

Motivation & Objective

• To implement the EIC Yellow Report's detector parameters into the Delphes framework for fast simulation.
• To enable rapid benchmarking of observables such as jets, missing transverse energy, and charm tagging using event generators like Pythia 8.
• To provide a community-ready, updatable simulation tool that complements detailed Geant4-based studies.
• To support the growing EIC collaboration by offering a standardized, high-performance simulation platform.
• To validate key detector performance metrics—such as jet resolution and PID efficiency—against the EIC design goals.

Proposed method

• The EIC Yellow Report’s detector specifications for tracking, calorimetry, and particle identification were encoded into a Delphes configuration card for both 1.5 T and 3.0 T magnetic field scenarios.
• Event generation used Pythia 8.3 with a 10 GeV electron beam and 275 GeV proton beam at √s = 105 GeV to simulate electron-proton collisions.
• Jet reconstruction employed the anti-kT algorithm with R = 1.0 using energy-flow objects as input, consistent with Delphes' standard implementation.
• Missing transverse energy (MET) was computed as the magnitude of the vector sum of transverse momenta of all energy-flow objects at both generator and reconstructed levels.
• Charm tagging was implemented via a displaced track-counting method using 3D impact parameter significance (sIP₃D) and track kinematic criteria: pT > 0.5 GeV, |sIP₃D| > 3, and d₀² + z₀² < 3 mm.
• Particle identification used 3σ separation criteria between e/π, K/π, and K/p, with efficiency maps defined for |η| < 3.5 and momenta up to 50 GeV.

Experimental results

Research questions

• RQ1 How well does the Delphes card reproduce key detector performance metrics—such as jet energy resolution and MET resolution—for EIC conditions?
• RQ2 What is the charm tagging efficiency for jets in charged-current DIS events using a displaced track-counting method?
• RQ3 How effective is the implemented particle identification scheme in distinguishing electrons, pions, kaons, and protons across the relevant momentum range?
• RQ4 To what extent can the Delphes card serve as a fast, accurate alternative to full Geant4 simulations for EIC physics studies?
• RQ5 Can the parametrized detector model be easily updated with refined Geant4 results to maintain accuracy while preserving simulation speed?

Key findings

• The jet-energy resolution for anti-kT jets with R = 1.0 was found to be consistent with expectations from the EIC Yellow Report, with resolution improving at higher transverse momentum.
• Missing transverse energy resolution was evaluated in charged-current DIS events, showing MET performance suitable for kinematic reconstruction via the Jacquet-Blondel method.
• The displaced track-counting charm tagging method achieved a measurable efficiency for charm jets, with the efficiency curve showing clear separation from light-flavor jets in the sIP₃D distribution.
• Particle identification efficiency curves demonstrated 3σ separation between electrons and pions, and pairwise 3σ separation between kaons, pions, and protons, with high efficiency for pions and kaons at momenta below 20 GeV.
• The simulation results for event displays (e.g., single-jet, di-jet events) confirmed the physical realism of the Delphes card in capturing key final-state topologies.
• The Delphes card is publicly available and designed to be updated with refined parameters from future Geant4 studies, ensuring long-term utility and accuracy.