The organization
Nikhef is the national institute for subatomic physics in the Netherlands. At Nikhef, approximately 250 physicists and 80 technical staff work together in an open and international scientific environment. Together they perform theoretical and experimental research in the fields of particle and astroparticle physics. Nikhef is a partnership between six major Dutch universities and NWO-I Foundation, the Institutes Organization of the Dutch Research Council (NWO).
Among the research collaborations Nikhef participates in are the ALICE, ATLAS and LHCb experiments at CERN, the KM3NeT neutrino telescope in the Mediterranean, the Virgo gravitational waves interferometer in Pisa, the Xenon-nT dark matter experiment in Gran Sasso, the Pierre Auger cosmic ray observatory in Argentina, and the eEDM research programme in Groningen. There are also scientific groups on Theory, Physics Data Processing and Detector R&D. Nikhef avails over excellently equipped technical departments in mechanics, electronics and computing.
The Nikhef ATLAS group
The Nikhef ATLAS group consists of a total of 15 scientific staff, typically 5 postdocs and 15 PhD students. As a founding member of the ATLAS collaboration, the group has a long-term involvement in detector construction (the semiconductor tracker, barrel muon chambers, readout, alignment, and data acquisition).
For the phase-2 upgrade (2027-2030), we will instrument and commission one of the end-caps of a new all-silicon inner tracking system (ITk) in Amsterdam, commission the High Granularity Timing Detector (HGTD), and develop the new universal readout system (FELIX) for ATLAS detector systems.
The group also has a strong record in track reconstruction, flavour tagging algorithm development as well as physics data analysis, with a focus on Higgs boson physics, top quark physics, and searches for new physics signatures.
The positions
After the discovery of the Higgs boson in 2012, one of the crucial future challenges for the LHC is to probe its most enigmatic property, the Higgs potential, which can manifest itself in LHC collisions through the production of Higgs boson pairs. These decays, which are 1000 times more rare than single Higgs production according to the Standard Model have not yet been observed. Observation of two-Higgs production is one the most important milestone for the LHC physics program, and will help constrain our knowledge of the Higgs potential, which has shaped the universe at its time of creation, and may hold strong clues about the existence of new physics beyond the Standard Model.
Position 1 will focus on two-Higgs production to a pair of b-quark jets and a pair of vector bosons, with additional emphasis on the use of multi-object triggers for event selection. The research will also focus on the final state where the vector bosons decay hadronically, introducing a new search channel that may play a pivotal role in enhancing the overall sensitivity of the analysis. This position is co-supervised by prof. dr. Pamela Ferrari, dr. Flavia de Almeida Dias, and prof. dr. Nicolo de Groot. The candidates is employed by NWO institute Nikhef, is primarily based in Amsterdam with the PhD degree granted by the Radboud University
Position 2 will focus on a pioneering machine learning-based end-to-end optimization of selection criteria for all two-Higgs decay signatures, including the criteria for object selection for the Higgs decay objects (W, Z, b, τ and γ). This highly complex optimization will be based on a surrogate model to make it tractable, and will be cross-validated after optimization with a traditional likelihood model. This position is co-supervised by dr. Sascha Caron and prof. dr. Wouter Verkerke. The candidate is employed by NWO institute Nikhef, is primarily based in Nijmegen, and granted the PhD degree by the Radboud University.
The positions offered here are part of a NWO-funded physics program “The potential of the Higgs boson”, which will ultimately comprise 7 PhD positions and 2 postdoc positions in the Nikhef ATLAS group in the period 2025-2030 all focused on the Higgs boson potential, complemented by 9 Nikhef staff scientists that offer supervision, networking opportunities and a specialized training program in data analysis techniques and Higgs boson physics.
Requirements
We are looking for PhD candidates with an (almost) completed Master degree in high-energy physics or in a closely related field. The ideal candidate has a strong interest in data analysis, has good software skills (Python, C++, ROOT) and has (some) research experience in experimental particle physics. Experience with machine learning algorithms and software is desirable but not required.
Offer
A temporary fulltime contract for the duration of 4 years. This should lead to a dissertation (PhD thesis). We will draft an educational plan that includes attendance of courses and (international) meetings. We also expect you to assist in teaching undergraduates and master students. During the doctoral program there is the possibility for extended stays at CERN, up to a total of 1 year.
You will be employed at either the NWO-I-foundation. The gross monthly salary, based on 38 hours per week and dependent on relevant experience, ranges between € 2,968 to € 3,801 gross per month. The salary is based on a full-time contract. On top of the monthly salary, excellent secondary benefits apply, such as a 8% holiday allowance in May, and a 8.3% year-end allowance in December and an excellent pension plan. Further details on the conditions of employment of the NWO-I-foundation can be found on www.nwo-i.nl.
Application
Qualified applicants are encouraged to apply by filling in the template below. The deadline for applications is June 10th, 2025. Please be prepared to upload a short cover letter, a curriculum vitae and have the email address of at least two referees ready who are willing to send a letter of recommendation on your behalf. A knowledge security check can be part of the selection procedure.
Please indicate in which position(s) you are interested in your cover letter. Interviews with selected candidates are foreseen in the week of July 1st. For further information, feel free to contact list co-supervisors for details on the positions, or prof. dr. Wouter Verkerke for general information about the Nikhef ATLAS group.
About Radboud University
Radboud University, based in Nijmegen, hosts approximately 24,000 undergraduate students on one of Europe’s greenest campuses. Its Science Faculty is subdivided into six research institutes and neighbours the FELIX-HFML national research institute; its contributions to the ATLAS experiment (and to subatomic physics at large, as well as astroparticle and gravitational physics) are embedded in the Institute for Mathematics, Astrophysics and Particle Physics (IMAPP). Radboud University is one of the founding members of the Nikhef joint venture, and has a long history of participation in collider physics experiments.
NWO-I is an equal-opportunity employer. We prioritise diversity and are committed to creating an inclusive environment for everyone. We value a spirit of enquiry and perseverance, provide the space to keep asking questions, and promote a culture of curiosity and creativity.