07 February 2026 Saturday

• See above

• Filled out poll for Markus
• Scheduled Sindhu Annual review
• Signed PGSS offer letter
• Mail to SAM
• Fixed counter culture address
• Mail re: HS student Advice to High-School Students interesting in physics
• Letter for Chuyuan

Hi Christian,

Here is the first part of the instructions to get you started.

Our code consists of two main components:

• Barista (https://gitlab.cern.ch/cms-cmu/barista (https://gitlab.cern.ch/cms-cmu/barista)): A base class containing generic tools

for various analyses, such as file access in EOS and object corrections.

• Coffea4bees (https://gitlab.cern.ch/cms-cmu/coffea4bees (https://gitlab.cern.ch/cms-cmu/coffea4bees)): The specific code for

HH4b analysis.

You can find more details in our documentation here: https://barista.docs.cern.ch/ (https://barista.docs.cern.ch/). Since the framework is based on Coffea, you may also find this tutorial helpful: https://coffea-hep.readthedocs.io/en/latest/examples.html (https://coffea-hep.readthedocs.io/en/latest/examples.html).

You will be assisting with "skimming," where we take centrally produced nanoAOD files, apply loose selections to remove unnecessary information, and store smaller root files for further processing. We have already completed skims for 2022–2023; we will now focus on 2024.

Setup Instructions:

1. In your no_backup area on your cmslpc account, follow the quickstart guide to set up the framework:

https://barista.docs.cern.ch/bbbb/#quickstart (https://barista.docs.cern.ch/bbbb/#quickstart).

1. Key Scripts:
2. run_container: A wrapper that sets up the software environment (cmslpc, lxplus, or falcon) and allows you to run Coffea,

Python, or Awkward code inside an analysis container.

• runner.py: The main script that manages files, processors, and output. You can view the available options by running: .

/run_container python runner.py –help. (PD: all our code always contains a `–help` argument. You can run `./run<sub>container</sub> –help` for instance.)

To verify your setup, please run the following test (ensure your certificate is set up first):

cd barista/ ./run_container bash coffea4bees/scripts/skimmer-test.sh

Please let me know once this finishes successfully without errors, and I will send over the next set of instructions.

• See above