Tasks 1-3

Last updated on 2026-07-12 | Edit this page

Estimated time: 180 minutes

Overview

Questions

  • Information and objectives for tasks 1-3

Objectives

  • Find the first three parts of the file name!

Task 1 - eic-shell Versioning

eic-shell contains all of the software we need to do an EIC/ePIC analysis. To get started on this task, and all of the others, you will need eic-shell working on either your local machine, or a computing cluster you can access (e.g. BNL or JLab systems). Instructions on installing eic-shell can be found in the Setting Up Your EIC Environment tutorial.

Typically, you should use the latest version of this container. However, on some occassions you may want to reproduce an earlier analysis or result that used a different version of the software within the container. You can see what versions of eic-shell are available on the eic_xl container registry. You can check your current version from eic-shell:

BASH 

eic-info

Your current version is listed at the bottom of this output at the output next to “jug_dev:”. By default, you are likely running the “nightly” release which is the most up-to-date. For this scavenger hunt training activity, we will work from a different, common release.

For this task, you will switch your eic-shell version to the one specified in the channel header of the scavenger-hunt mattermost channel. See the instructions on the ePIC getting-started guide on how to join mattermost if you’re not there already. Either browse and join the channel or follow this link to the scavenger-hunt Mattermost channel.

Challenge

Exercise: Switch container version

  • Switch to the container version specified in the header of the scavenger-hunt mattermost channel.
  • To begin, download the install.sh script:

BASH 

wget --output-document install.sh https://get.epic-eic.org
./install.sh -v <<version>>
eic-shell

Running eic-shell should now open the specified version. You can check this by running “eic-info”. Now you can open root to check your root version.

BASH 

root --version

The version output will printed in the format 6.XX.YY. These numbers XX and YY will be used in the next part of the challenge to find your campaign files. Use them in the answer checker at the bottom of this page!

After installing and launching the specified container, eic-info reports the version you selected and root --version prints 6.XX.YY. Record the XX and YY numbers for the answer checker.

Callout

Comment:

  • If you are using a system with CVFMS enabled, such as the JLab farm, you can also run:
    • ./eic-shell --version <<version>> once eic-shell is installed

Task 2 - Browsing and Copying Campaign Files

Regular simulation campaigns are run on a monthly basis. In these campaigns, physics and background events are passed through the latest version of the ePIC simulation and reconstruction software.

Information on browsing and copying files from simulation campaigns is outlined in the File Access tutorial. Further information on the campaigns can be found on the production working group pages.

From above, you will access the campaign files in MM=(XX-2)/ 10 in the year 2026. This will follow the format 26.MM.1 (where if MM<10, you will put a 0 in front of the number).

Challenge

Exercise: Copy a campaign file

Inserting the number you got for MM:

  • Download a file with the DID epic:/RECO/26.MM.1/epic_craterlake/EXCLUSIVE/DVCS_ABCONV/EpIC_v1.1.6-1.2/10x100/q2_1_100/EpIC_1.1.6-1.2_DVCS_BH_10x100_q2_1_100_minus_abconv_run0.0MM1.eicrecon.edm4eic.root (replacing MM with the number you obtained above)
    • You can check you got the right DID using the answer checker at the bottom of the page.
  • How many entries are within the branch elements of VertexBarrelHits for this file?
  • Enter your answer into the checker to get the next clue!

Once the file is copied locally you can open it in ROOT and inspect the VertexBarrelHits branch (for example with events->Draw("VertexBarrelHits.eDep") another collection within the branch). Enter the number of entries into the answer checker to receive the clue.

Task 3 - Differences Between Event Generators

Many event generators exist for a wide range of processes. In some cases, the same process can be simulated using two different versions of the same generator. The output of the two versions can differ. In this task, we will examine the reconstructed output differences from BeAGLE1.03.02-1.0 and BeAGLE1.03.02-1.3. Below replace NN with the solution to NN = YY + 2*MM - 1.

Challenge

Exercise: Compare two generator versions

Inserting the numbers you got for MM and NN:

  • Grab files from the following DIDs: epic:/RECO/26.MM.1/epic_craterlake/DIS/BeAGLE1.03.02-1.0/eH2/10x130/q2_1to1000/BeAGLE1.03.02-1.0_DIS_eH2_10x130_q2_1to1000_ab.00NN.eicrecon.edm4eic.root and epic:/RECO/26.MM.1/epic_craterlake/DIS/BeAGLE1.03.02-1.3/eH2/en/10x130/q2_1to1000/BeAGLE1.03.02-1.3_DIS_eH2_en_10x130_q2_1to1000_ab_run001.00NN.eicrecon.edm4eic.root

    • You can check you got the right DIDs using the answer checker at the bottom of the page.

  • Check the mean of the GeneratedJets.energy in each file.

  • From the mean values of the GeneratedJets.energy histograms (no cuts). Select the correct set of two values in the answer checker to get the clue from task 3!

Open each file in ROOT and histogram GeneratedJets.energy with no cuts (events->Draw("GeneratedJets.energy")), then read the histogram mean from each. Select the pair of mean values in the answer checker to obtain the task 3 clue.

Answer Checker

Key Points
  • Find the first three parts of the file name!