Neutrino Programme
Programme Leader
Paul de Jong, Dorothea Samtleben (deputy)
Main points: scientific
ANTARES
- Hints for TeV neutrino emission from the galactic ridge.
- Search for spatial correlations of neutrinos with ultra-high-energy cosmic rays.
- Search for correlations between high-energy gamma rays and neutrinos with the HAWC and ANTARES detectors.
- Limits on beyond-the-standard model physics scenarios, including nuclearites, magnetic monopoles and non-standard neutrino interactions, with 10 years of ANTARES data.
KM3NeT
- Measurement of neutrino oscillations and limits on neutrino decay and non-standard neutrino interactions in KM3NeT/ORCA.
- First searches for cosmic neutrino point sources with KM3NeT/ARCA.
- First follow-ups of alerts of possible transient sources from other experiments.
- Implementation, commissioning and running of a real-time core-collapse supernova neutrino detection system, including sending of alerts.
- Observation of cosmic ray shadow of Sun and Moon with KM3NeT/ORCA.
DUNE
- Physics performance studies, e.g. on supernova neutrino detection, low-exposure long-baseline neutrino oscillation sensitivity, oscillation analysis systematics, and sensitivity to physics beyond the Standard Model.
Main points: technical
ANTARES
- Shutdown of ANTARES in February 2022, and recovery of detector elements.
KM3NeT
- Deployment of ORCA Detection Units (DUs) and growth of ORCA to data taking with 14 DUs (~250 optical modules) by the end of 2022.
- Deployment of ARCA DUs and growth of ARCA to data taking with 21 DUs (~375 optical modules) by the end of 2022.
- Further mass production of Digital Optical Modules and DUs.
- Reconstruction and event classification software, general software, oscillation and cosmic neutrino analysis software frameworks.
- Calibration, including dynamical position calibration of optical modules in the sea with acoustics.
DUNE
- Further advances in the design of DUNE: evolution of near-detector design, completion of the offline computing conceptual design report, advances in photon detection system and the further development of the vertical-drift detector concept.
- Construction of the ProtoDUNE 2 detectors at CERN.
- Excavation of the DUNE Far Detector cavities has started.
Grants
- Infradev2: Towards full implementation of the KM3NeT research infrastructure
- Netherlands eScience Center grant: A database-integrated KM3NeT solution for automated processing (DIKSAP)
- NWO computing grant: Computing for (Proto)DUNE 2
- Horizon Europe Marie-Curie staff exchange program for DUNE: “SENSE”
Key positions in collaborations
KM3NeT
- Physics and software manager: Aart Heijboer
- Software/computing co-coordinator: Mieke Bouwhuis
- Detection Unit integration coordinator: Daan van Eijk
- Optical systems coordinator: Jan Willem Schmelling
- Project control officer: Antonio D’Amico
- Mechanics coordinator: Edward Berbee
- Cosmic ray physics group convener: Ronald Bruijn
- Calibration group co-convener: Dorothea Samtleben
- EU Liaison officer: Maarten de Jong
- System Engineer: Ernst-Jan Buis (TNO)
ANTARES
- Point sources group co-convener: Dorothea Samtleben
- Conference committee chair: Mieke Bouwhuis
Main papers in 2022
ANTARES
- Hint for a TeV neutrino emission from the Galactic Ridge with ANTARES, arXiv:2212.11876, submitted to Astronomy and Astrophysics
KM3NeT
- Implementation and first results of the KM3NeT real-time core-collapse supernova neutrino search, Eur. Phys. J. C 82 (2022) 4, 317
DUNE
- Design, construction and operation of the ProtoDUNE-SP liquid argon TPC, JINST 17 (2022) 01, P01005
Cosmic Rays (Pierre Auger Observatory & GRAND)
Programme Leader
Charles Timmermans
Main points: scientific
- Auger Radio Detector Upgrade prototypes performance as expected; air showers seen in the new Radio Detector combined with the Surface Detector
- A complete spectrum of cosmic rays from 0.1 EeV to beyond 100 EeV
Main points: technical
- AugerPrime (excluding Radio) close to 100% installed
- GRANDProto redistributed. 2 sites will be explored simultaneous, one in China and one in South America
- Array Auger Radio electronics delivery of parts is slowing down installation
Awards, fellowships, grants, etc.
- Prof. David Nitz received a Radboud Excellence Initiative (REI) professorship in 2022
- Teresa Bister obtained an REI excellence fellowship, started 1/1/2023.
- SURFsara Grid resource grant renewed
Key positions in collaborations
- Auger radio group leader: Jörg Hörandel
- GRAND technical coordinator: Charles Timmermans
Main paper in 2022
- Cosmological implications of photon-flux upper limits at ultrahigh energies in scenarios of Planckian-interacting massive particles for dark matter, The Pierre Auger Collaboration, Phys.Rev.D 107 (2023) 4, 042002
Dark Matter
Programme Leader
Patrick Decowski
Main points: scientific
- XENONnT has been taking data since May 2021 with 8.6 tons of liquid xenon. The initial science run (SR0) with 90 live days of data taken in 2021 was followed with a detailed calibration campaign and then with the start of a 2nd science run (SR1).
- Significant progress has been made on all the subsystems of XENONnT, especially the liquid xenon purification system, the radon distillation column as well as the neutron veto. Several unparalleled detector parameters were achieved and maintained during SR1: an electron lifetime of > 20 ms and a radon level of < 1 𝝻Bq/kg.
- During SR0 and SR1 we operated the TPC with a drift field of ∼23V/cm and electron extraction efficiency of ∼ 50% (compared to 90% achieved in XENON1T) due to an electrical shortcut preventing us to reach the nominal electrode voltages, likely associated with a broken wire in one of the electrodes. New electrodes are being fabricated and tested to prepare for the possible replacement of the current electrodes in the TPC. The replacement would require the disassembly of the neutron veto and TPC detectors and incur substantial science data taking downtime.
- On the analysis side, we reported a blind analysis searching for new physics in the low-energy electronic-recoil data from the first XENONnT Science Data (SR0). The background level in the search region (1, 30) keV is the lowest ever achieved in a dark matter detector and about five times lower than that of XENON1T. The unprecedented low background and the agreement between data and expectations gave new world-leading upper limits on solar axions, enhanced neutrino magnetic moment, and bosonic dark matter. This null result leaves only the tritium hypothesis as a possible explanation of the XENON1T excess reported in 2020. In XENONnT, tritium was suppressed with improved xenon handling and detector preparation. The SR0 nuclear recoil data are still blinded while the analysis for the WIMP search is being finalized.
- The Nikhef-designed triggerless data-acquisition system continues to work extremely well. The flexibility of this system allowed the readout to be adapted to the unexpected low-field situation. The rapid raw data processing also allows a first pass towards reconstructed data, simplifying offline data processing at remote sites. We are currently working on implementing an adaptable software veto for high-rate conditions during calibrations and improved monitoring tools.
- The XLZD consortium formed from the two leading liquid xenon dark matter collaborations LZ and DARWIN/XENON with the goal to build a 50t liquid xenon detector. We had a first joined meeting in the summer and an active community is working towards a design document for the future experiment.
- We published a white paper describing the many XLZD/DARWIN science goals showing that this large liquid xenon detector will become a true low-background observatory.
Main points: technical
- Many ongoing R&D activities in the Nikhef XAMS and VUV labs. The XAMS TPC was redesigned for better liquid xenon handling and flexibility. Many of the other XAMS systems were upgraded for better performance.
Key positions in collaborations
- XENON Editorial Board: Patrick Decowski
- XENONnT Technical Coordinator: Auke-Pieter Colijn
- DARWIN Executive Board: Patrick Decowski
- DARWIN Simulations and Sensitivity Studies WG Leader: Tina Pollmann
- XLZD Steering Committee: Patrick Decowski
- XLZD Working Group Coordination: Tina Pollmann
Main paper in 2022
“Search for New Physics in Electronic Recoil Data from XENONnT”, XENON Collaboration, Phys. Rev. Lett. 129, 161805 (2022); arXiv:2207.11330.
Gravitational Waves
Programme leaders
Stefan Hild
Chris Van Den Broeck, Andreas Freise (deputies)
Main points: scientific
- Nikhef became third member of the European Gravitational Observatory (EGO), next to INFN and CNRS
- Final O3 analyses published
- National Growth funds approved (42+870 MEuro for ET), LISA roadmap proposal approved, ENW-XL@Utrecht for nuclear matter, next Virgo consortium approved (NWO infrastructure)
- O4 run starting in 2023. Run extended from 12 to 18 months on request of astronomy community.
Main points: technical
- Advanced Virgo + (Phase 1 completed): Strong hardware contribution from Nikhef, i.e. filter cavity for frequency dependent squeezing.
- ETpathfinder came really to life!
Key positions in the collaboration
- Matteo Tacca: Virgo commissioning coordinator 2020-2022.
- Alessandro Bertolini: AdV+ project, Filter Cavity subsystem manager since 2018.
- Bas Swinkels: AdV+ project, Electronics, Software and Controls system manager until 2022.
- Sebastian Steinlechner: AdV+ project, Optical System Design subsystem manager since 2020.
- Henk-Jan Bulten: AdV+ project, SBE subsystem manager since 2020.
- Jessica Steinlechner: co-chair of the Optics working group of the LIGO Scientific collaboration.
- Peter Pang (PhD student): coordinator of parameterized tests of GR for the dynamics of binary black hole mergers.
- Andreas Freise: Einstein Telescope Instrumentation Science Board co-chair 2019-2022.
- Andreas Freise: Einstein Telescope directorate
- Stefan Hild: Einstein Telescope Instrumentation Science Board co-chair, since 2022.
- Stefan Hild: Project leader of ETpathfinder
- Stefan Hild: Project leader of ET Technologies consortium
- Stefan Danilishin: Einstein Telescope Instrumentation Science Board co-chair of interferometer division, since 2022.
- Chris Van Den Broeck: Einstein Telescope Observational Science Board co-chair for Division 1 (Fundamental Physics) and Division 10 (Data Analysis Platform) since 2021.
Main papers in 2022
- All-sky search for gravitational wave emission from scalar boson clouds around spinning black holes in LIGO O3 data, Phys. Rev. D 105 (2022) 102001
- Constraints on dark photon dark matter using data from LIGO’s and Virgo’s third observing run, Phys. Rev. D 105 (2022) 063030
- All-sky search for continuous gravitational waves from isolated neutron stars using Advanced LIGO and Advanced Virgo O3 data, Phys. Rev. D 106 (2022) 102008
- ETpathfinder: a cryogenic testbed for interferometric gravitational-wave detectors, Class. Quantum Grav. 39 (2022) 215008
- Constraining Neutron-Star Matter with Microscopic and Macroscopic Collisions. Nature, volume 606, pages 276–280 (2022)