Two PhD candidates in the ATLAS group

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 at the LHC, the hunt for physics beyond the Standard Model (SM) has intensified. A wide range of possible new physics scenarios at high energy scales can be described by the theoretical framework SM Effective Field Theory (SM-EFT) at energy scales below where new interactions could be directly observed, and which are currently accessible by the LHC. Subtle effects at LHC energy scales may be expected in process that involve the two most massive particles of the SM, the top quark and Higgs boson. The top-Higgs interaction is currently poorly constrained, but new deep learning techniques that exploit the structure of the Lagrangian provide a tantalizing chance to probe anomalous couplings with unprecedented precision. In SM Effective Field Theory anomalous top-Higgs interactions are expressed in the operator Oφt, which remains one of the most poorly constrained operators of SM-EFT to date. Position 1 will focus on Higgs boson production through the ggàHZ process, where the top quark contributes via a quantum loop and is therefore sensitive to top-Higgs interactions. This process is interesting by itself as of today no separate measurement of its cross section is available due to the large background of the qqàHZ process. The use, and further development, of modern techniques such as Transformer networks open a window to exploring this process. Position 2 will focus on new experimental results to extract poorly constrained SMEFT coefficients of the corresponding operators, including Oφt, which models anomalous top-Higgs interactions. Understanding systematic effects and their propagation in deep learning networks is crucial for this project. The playground for this study is initially provided by the gg->HZ and rare top-quark processes, including the tZq process, and then gradually extended to other process. Both positions are jointly supervised by prof. dr. Marcel Vreeswijk and prof. dr. Wouter Verkerke. The positions offered here are funded by the NWO-M2-project “When Higgs bosons meet Top quarks” and embedded in the Nikhef ATLAS group. Candidates will be employed by the University of Amsterdam, and will be based at Nikhef in Amsterdam. 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 We offer a temporary contract for 38 hours per week for the duration of 4 years (the initial contract will be for a period of 18 months and after satisfactory evaluation it will be extended for a total duration of 4 years). The gross monthly salary, based on 38 hours per week ranges between € 3,059 to € 3,881 (Scale P). This does not include 8% holiday allowance and 8.3% year-end allowance. The UFO profile PhD candidate is applicable. A favourable tax agreement, the ‘30% ruling’, may apply to non-Dutch applicants. This employment 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. Further details can be found here . Application Qualified applicants are encouraged to apply by filling in the template below. The deadline for applications is March 8th, 2026 . 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. Please note that reference letters will only be requested for selected candidates after the application deadline has passed. 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 first half of April. 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.