Summary and Setup

Welcome to the EIC/ePIC tutorial on PODIO and track-cluster matching! This tutorial will illustrate the basics of PODIO and how to use it in an analysis setting via track-cluster matching.

Prerequisite

Prerequisites

You will need experience/knowledge with the following topics:

• Using CERN ROOT and/or Python;
• Working on the command line in UNIX environments;
• And the eic software environment.

This builds on other tutorials in the EIC series:

• Setting up your environment
• Accessing EIC files
• Analysis basics

Further information is included in other tutorials:

• Understanding the Simulation Output
• Kinematic Reconstruction
• Reconstruction Algorithms in JANA2
• Simulations Using DDsim and Geant4
• Geometry Development with DD4hep
• Modifying Geometry, Digitization, Etc
• Developing Benchmarks

If you have not done so already, please follow the environment setup tutorial well before the start of the tutorial to ensure your system is ready. You will need a working eic-shell environment running.

This tutorial will cover the basics of PODIO and illustrate how to use it in an analysis setting through the lens of a critical operation in our reconstruction, matching tracks to clusters. We will also touch on other examples of how to use PODIO in your analysis such as identifying the decay electrons of a \(J/\psi\). Examples of how to do the same analyses in other formats — such as with RDataFrame or with TTreeReader — are included as extras at the end of the tutorial (TODO).

We will need a file to process for the example code, so if you havent done so yet, please follow the tutorial on accessing EIC/ePIC simulation data with Rucio. We suggest using a file with an enhanced rate of \(J/\psi\). For example, you can run the following command in the eic-shell:

BASH

xrdcp root://epicxrd1.sdcc.bnl.gov:1095//eic/EPIC//RECO/26.04.1/epic_craterlake/EXCLUSIVE/DIFFRACTIVE_JPSI_ABCONV/lAger3.6.1-1.0/10x130/hiAcc/lAger3.6.1-1.0_jpsi_10x130_hiAcc_run1.0009.eicrecon.edm4eic.root ./

Lastly, you may want to work through some sections of the introductory analysis tutorial. In particular, the episode on the reconstruction output tree touches on the structure of the ROOT trees we’ll be analyzing.