Tasks 7-8

Last updated on 2026-07-10 | Edit this page

Overview

Questions

  • Information and objectives for tasks 7-8

Objectives

  • Find the final two parts of the file name!

Task 7 - Exploring a Reconstructed Output File

In this task, we will take a closer look at the branches contained within a reconstruction file. You may find lesson 2 of the analysis tutorial to be useful here if you have not looked at analysis files before.

Challenge

Exercise: Count ZDC branches

  • Using the file - epic:/RECO/25.10.2/epic_craterlake/EXCLUSIVE/UCHANNEL_PI0/18x275/pi0_18x275_uChannel_Q2of0to10_hiDiv.0104.eicrecon.edm4eic.root, do the following:
  • Check the number of branches this file contains
    • Find the number of branches that contain ZDC within their name, do not include branches that begin with _
    • Check how many elements the “ReconstructedFarForwardZDCNeutrals” branch collection has
    • Select the corresponding values in the answer checker at the bottom of this page to get your clue for task 7!

Open the file in ROOT and list the branches (for example events->GetListOfBranches()->GetEntries()). Count those whose name contains ZDC and does not start with _, then check the element count of the ReconstructedFarForwardZDCNeutrals collection. Select the matching values in the answer checker to receive the task 7 clue.

Task 8 - Using MC Particles

In this task, we will do a basic analysis of some information contained within a reconstruction file. Namely, we will look at the inforrmation in the MCParticles branch. Accessing the truth information is very important in simulation studes. You may find lesson 3 of the analysis tutorial to be useful here if you have not looked at analysis files before.

Challenge

Exercise: Reconstructed stable final-state particles

  • Using the file - epic:/RECO/25.10.2/epic_craterlake/EXCLUSIVE/UCHANNEL_PI0/18x275/pi0_18x275_uChannel_Q2of0to10_hiDiv.0104.eicrecon.edm4eic.root, the same as Task 7, do the following using the MCParticles branch:
    • Determine the number of stable, final state electrons that have an associated reconstructed particle
    • Determine the number of stable, final state photons that have an associated reconstructed particle
    • Enter your corresponding values into the answer checker at the bottom of the page to get your clue for task 8!

Loop over MCParticles, keeping stable final-state electrons and photons, and use the ReconstructedParticleAssociations collection to keep only those with an associated reconstructed particle. Enter the two counts (electrons and photons) into the answer checker to receive the task 8 clue.

Callout

Comment:

  • You will need to utilise the ReconstructedParticleAssociations collection to find whether your MC particles have an associated reconstructed particle or not.

Answer Checker

Key Points
  • Find the final two parts of the file name!