Lead Experimental Particle Physicist (EP-FCC-2026-83-LD)

At CERN, the European Organization for Nuclear Research, physicists and engineers are probing the fundamental structure of the universe. Using the world's largest and most complex scientific instruments, they study the basic constituents of matter - fundamental particles that are made to collide together at close to the speed of light. The process gives physicists clues about how particles interact, and provides insights into the fundamental laws of nature.

Introduction:

You will lead hands-on research and development activities for the FCC-ee experimental program, focusing on beam-induced backgrounds, machine–detector interface studies, and detector optimisation to achieve the desired systematic uncertainties in precision measurements at the Z pole. The role combines technical leadership with active involvement in simulation, detector development, computing, and experimental validation to advance the design and performance of future FCC detectors.

Functions:

• Carry out and supervise research and development activities on the experimental environment of the future FCC electron–positron collider, with emphasis on beam-induced backgrounds (BIB) and their impact on detector performance, via the integration of realistic background conditions into detector simulation and data reconstruction workflows.
• Develop scalable workflows and software infrastructure ensuring optimal use of computing resources, to run large-scale and detailed beam-induced background simulations. Interpret the results of these simulations to quantify background sources originating from the accelerator,  assess their effects on particle detectors, readout strategies and data quality, and design and study strategies to mitigate these backgrounds in close collaboration with accelerator experts and detector designers.
• Develop methods to determine key limiting parameters directly from experimental data, towards enabling high-precision physics measurements at FCC-ee, including the definition of requirements for detector alignment, stability, and calibration needed to reach the targeted measurement precision.
• Contribute to the design and development of FCC-ee detector technologies, including hands-on work on prototypes, laboratory measurements and test-beam experiments, fostering collaboration between physicists, engineers, and software specialists.
• Present results in internal meetings, international workshops, and scientific conferences, and contribute to scientific publications and technical reports.

• PhD or equivalent relevant experience in the field of Experimental Particle Physics or a related field.
• You are asked to provide two reference letters as part of your application.

Experience:

Experience in the following areas is mandatory:

• Proficiency in particle physics data analysis, detector simulation, and collider experimental environment in e+e- collisions.
• Full knowledge of the FCC-ee precision physics programme and its implications on the required detector performance.
• Agility with programming languages (python, C++) and HEP software tools (ROOT, GuineaPig, BIB Monte-Carlo codes, …).
• Proven experience with supervision and team coordination.
• Familiarity in detector design and prototyping, and in machine-detector interface studies.

Demonstrated experience in the following areas will be considered as an advantage:

• Large scale computing infrastructures (e.g. Condor and workflow management systems).
• Electroweak precision measurements with collider data.

Technical competencies:

• Analysis and interpretation of experimental data.
• Analysis and optimisation of detector performance: detector/experiment.
• Simulation, design and development of (parts of) detectors.
• Knowledge and application of physics reconstruction techniques.
• Knowledge and application of statistical and numerical mathematical methods.

Behavioural competencies:

• Achieving Results: having a structured and organised approach towards work; being able to set priorities and plan tasks with results in mind.
• Learning and Sharing Knowledge: sharing knowledge and expertise freely and willingly with others; coaching others to ensure knowledge transfer.
• Communicating Effectively: delivering presentations in a structured and clear way; adjusting style and content to the audience; responding calmly and confidently to questions.
• Solving Problems: assimilating large quantities of information, identifying key issues and formulating conclusions clearly and concisely.
• Leading with Strength and Credibility: conveying and instilling energy, enthusiasm and ownership of CERN goals.

Language skills:

Spoken and written English, with a commitment to learn French.

Eligibility and closing date:

Diversity has been an integral part of CERN's mission since its foundation and is an established value of the Organization. Employing a diverse workforce is central to our success. We welcome applications from all Member States and Associate Member States.

This vacancy will be filled as soon as possible, and applications should normally reach us no later than 03.05.2026 at 23:59 CEST. 

Employment Conditions:

Contract type: Limited duration contract (5 years). Subject to certain conditions, holders of limited-duration contracts may apply for an indefinite position.

Working Hours: 40 hours per week

Job Flexibility: Hybrid

This position involves:

• Work during nights, Sundays and official holidays, when required by the needs of the Organization.

Job grade: 6-7

Job reference: EP-FCC-2026-83-LD

Field of work: Experimental Physics

Benchmark Job Title: Applied Physicist

Global Benefits

• A competitive salary (tax free), increasing in line with your years of relevant experience.
• 30 days of paid leave per year plus 2 weeks annual closure.
• Coverage by CERN’s comprehensive health insurance scheme (for yourself, your spouse and children), and membership of the CERN Pension Fund.
• Family, child and infant monthly allowances depending on your individual circumstances.
• A relocation package (installation grant, removal, travel expenses) depending on your individual circumstances.
• Possibility to extend your contract up to 8 years + eligibility for indefinite contract tenure.

Overview of CERN - Discover a world where the impossible is made possible!

At CERN, the European Organization for Nuclear Research, we are pushing the frontiers of science and technology. Our groundbreaking work brings together not only physicists but also a diverse range of professionals from engineering, technical, scientific, and administrative fields. Together, we foster an environment where innovation and collaboration thrive.

Every day, we face exciting new challenges and opportunities to contribute to cutting-edge research that shapes our understanding of the universe. We meet these challenges through the diverse perspectives within our teams, ensuring every contribution is valued and driving our shared sense of inclusion and purpose. Diversity is a core value of CERN since its foundation, and it remains central to our mission and continued success.

If you are ready to be part of a dynamic, inclusive community pushing the boundaries of knowledge, CERN is the place where your curiosity and skills can thrive. Be part of our mission to uncover what lies at the heart of the universe! TAKE PART!

More information about us, here: careers.cern