Sébastien Wertz
Technical Expert at Yuma
Walhain-Saint-Paul, Walloon Brabant, Belgium
Summary
🤩
Rockstar🎓
Top SchoolSébastien Wertz is a Technical Expert with 11 years of experience bridging high-energy physics research and production-grade software engineering. He holds a PhD in Elementary Particle Physics and has transitioned from postdoctoral roles at top European institutes to technical leadership positions in consulting and industry, currently at Yuma and B12 Consulting. An active back-end contributor to the prominent CMS/cms-sw and nanoAOD tooling projects, he has implemented robust solutions for NanoAOD weight handling, jet energy corrections, and b-tagging scale factors used by the LHC analysis community. Comfortable navigating both complex scientific codebases and client-facing technical challenges, he brings rigorous validation practices and an eye for edge cases—evident in commits that protect against empty weight arrays and address subtle detector issues. Based in Walhain-Saint-Paul, Belgium, he combines deep domain knowledge with practical tooling improvements that make large-scale physics data workflows more reliable.
11 years of coding experience
6 years of employment as a software developer
Doctor of Philosophy - PhD Elementary Particle Physics, Doctor of Philosophy - PhD Elementary Particle Physics at Université catholique de LouvainErasmus programme Physics, Erasmus programme Physics at Aarhus UniversityHigh School Diploma, High School Diploma at Bischöfliche Schule St.Vith
French, English, German
Github Skills (7)
root-view10
c-language10
high-energy-physics10
cprogramming-language10
python10
document-root10
nano10
Programming languages (15)
Github contributions (5)
cms-sw/cmssw
Sep 2018 - Jan 2023
CMS Offline Software
Role in this project:
Back-end Developer
Back-end DeveloperContributions:88 reviews, 115 commits, 26 PRs in 4 years 4 months
Contributions summary:Sébastien primarily contributed to the `PhysicsTools/NanoAOD` repository, specifically focusing on modifying the `GenWeightsTableProducer.cc` file. Their commits introduce a flag to manage the storage of Process-Specific (PS) weights and add and modify PS weights for nanoDQM. These changes involved code checks, formatting, and adjustments to weight arrays to ensure proper handling and display of the weights within the NanoAOD framework. The user also addressed code formatting and protection against empty weight arrays.
cmscernweb-appc-plus-plusbackbonejs
cms-nanoAOD/nanoAOD-tools
Feb 2020 - May 2020
Tools for working with NanoAOD (requiring only python + root, not CMSSW)
Role in this project:Back-end Developer
Back-end DeveloperContributions:16 commits, 3 PRs, 20 comments in 3 months
Contributions summary:Sébastien has contributed to the development and maintenance of tools for working with NanoAOD data, a domain related to high-energy physics. Their work includes implementing jet energy corrections and uncertainties, specifically addressing issues like the HEM (Hadronic Endcap in Minus) issue. The user has also worked on improving the jet smearing process. Additionally, the user has made contributions to b-tagging scale factor implementations.
pythonazerothcorecmsswnanoaodmodular
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