PhD: modelling of high-energy hadronic interactions at AUGER, KM3NET, and FASER

The organization

Nikhef is the national institute for subatomic physics in the Netherlands. At Nikhef, approximately 220 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 the NWO-I Foundation, the Institutes Organization of the Dutch Research Council (NWO).

Nikhef participates in a wide range of research collaborations, including 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. Nikhef furthermore has scientific groups on theoretical particle physics, physics data processing, and detector R&D, and has excellently equipped technical departments in mechanics, electronics, and computing. Nikhef hosts a LHC Tier-1 data processing center and offers substantial additional computing resources for end-user data analysis and simulation.

Embedding
The research will be embedded in the Nikhef KM3NeT, Theory, and Cosmic Ray groups, and will also benefit from Nikhef's involvement in the FASER experiment. This research will form a cluster of connected research activities spanning hardware, computation, and fundamental physics across an exceptionally broad range of neutrino energies and sources. The KM3NeT group is building the KM3NeT neutrino telescope on the Mediterranean seafloor, covering the full chain from detector construction and calibration to event reconstruction and physics analysis. Its science programme spans neutrino source searches with ARCA, mass ordering measurements with ORCA, and cosmic ray studies through atmospheric muon measurements. The Cosmic Ray group, based in Nijmegen and Amsterdam, brings knowledge of air shower development, cosmic ray identification, and source searches, as well as shared experience in hardware development and data analysis. The FASER group extends this reach to the laboratory frontier: operating in the far-forward region of the LHC, FASER measures the highest-energy neutrinos ever produced at a human-made source, probing TeV-scale neutrino interactions under controlled conditions. Because these neutrinos originate from forward hadron production in proton-proton collisions, the same QCD and hadronic-interaction modelling that governs the FASER fluxes also underpins predictions of the atmospheric and astrophysical fluxes studied by KM3NeT and the Cosmic Ray group — making the collider-neutrino programme a precisely calibrated complement to the cosmic measurements. On the theoretical side, the Theory group's deep expertise in high-energy neutrino scattering, machine learning, and beyond-the-standard-model physics provides essential input to the interpretation of experimental results across the cluster, while they also work on effective field theories, QCD, and flavour physics.

Job summary:
The modelling of high-energy hadronic interactions is a dominant source of uncertainty in the interpretation of cosmic-ray air showers, high-energy astrophysical neutrino fluxes, and forward particle production at the LHC. The same underlying physics governs all three, yet the models used to describe it must be extrapolated far beyond the energies and phase-space regions where they have been directly measured.

The PhD candidate will improve the modelling of these high-energy hadronic interactions by confronting state-of-the-art models and event generators with measurements from three complementary experiments: ultra-high-energy cosmic-ray air showers at the Pierre Auger Observatory, high-energy neutrinos at KM3NeT, and forward neutrino and hadron production at FASER at the LHC. By combining these accelerator-based and astroparticle datasets within a common framework, the candidate will derive improved constraints on high-energy hadronic scattering, enhancing the physics reach of all three experiments.

The position

The successful candidate will be provided access to high-level data from Auger, KM3NeT, and FASER. The PhD candidate will be fully embedded in each of the three experimental groups for periods of 5/6 months each (for a total of 16 months per experiment during the 4 years of the PhD). Formally, the position will be embedded in the KM3NeT group in Nikhef. Although the position will be based in Amsterdam, for a period of six months the candidate will have significant physical presence in Nijmegen.

The three groups meet monthly in the new “Platform on extreme scattering modelling”, which ensures embedding in a broader community as well as continuity in supervision for the successful candidate.

Our research community is friendly and supportive. Nikhef is committed to being an inclusive and diverse organisation. Applications from women and people belonging to minority and underrepresented groups are especially welcomed.

Offer

The candidate will be employed by the NWO-I foundation for a period of 1+3 years and will obtain the status of PhD candidate. They will receive a competitive salary. The conditions of employment are excellent and include extra months’’salary payment in May and December. The conditions of employment of the NWO-I foundation can be found at

Requirements
Excellent software and programming skills, in particular in Python, as well as prior expertise in the topics relevant for this position are specially encouraged. Applicants should have a MSc degree in (astro-)particle or theoretical physics (or a closely related topic) by the time they start their appointment at Nikhef or shortly thereafter.