Theory
Programme Leader
Robert Fleischer
Spectrum of research highlights
- M. van Beekveld, E. Laenen, J. Sinninghe Damste and L. Vernazza, Next-to-leading power threshold corrections for finite order and resummed colour-singlet cross-sections
- Y. Li, I. Moult, S. Schrijnder van Velzen, W.J. Waalewijn and H.X. Zhu, Extending Precision Perturbative QCD with Track Functions
- R. Gauld, A. Gehrmann-De Ridder, E.W.N. Glover, A. Huss and I. Majer,
- VH+jet production in hadron-hadron collisions up to order $\alpha_s^3$ in perturbative QCD
- X. Chen, T. Gehrmann, E.W.N. Glover, A. Huss, B. Mistlberger and A. Pelloni, Fully Differential Higgs Boson Production to Third Order in QCD
- S. Moch, B. Ruijl, T. Ueda, J.A.M. Vermaseren and A. Vogt, Low moments of the four-loop splitting functions in QCD
- R.D. Ball et al., [NNPDF], An open-source machine learning framework for global analyses of parton distributions
- W. Cao, F. Herzog, T. Melia and J.R. Nepveu, Renormalization and non-renormalization of scalar EFTs at higher orders
- M. Borinsky, J.A. Gracey, M.V. Kompaniets and O. Schnetz, Five-loop renormalization of $\phi^3$ theory with applications to the Lee-Yang edge singularity and percolation theory
- R.A. Khalek, J.J. Ethier, E.R. Nocera and J. Rojo, Self-consistent determination of proton and nuclear PDFs at the Electron Ion Collider
- R.D. Ball, S. Carrazza, J. Cruz-Martinez, L. Del Debbio, S. Forte, T. Giani, S. Iranipour, Z. Kassabov, J.I. Latorre and E.R. Nocera, J. Rojo et al., The Path to Proton Structure at One-Percent Accuracy
- J.J. Ethier, R. Gomez-Ambrosio, G. Magni and J. Rojo, SMEFT analysis of vector boson scattering and diboson data from the LHC Run II
- A. Greljo, S. Iranipour, Z. Kassabov, M. Madigan, J. Moore, J. Rojo, M. Ubiali and C. Voisey, Parton distributions in the SMEFT from high-energy Drell-Yan tails
- J. de Vries, P. Draper, K. Fuyuto, J. Kozaczuk and B. Lillard, Uncovering an axion mechanism with the EDM portfolio
- Y.~\”Unal, D.~Severt, J.~de Vries, C.~Hanhart and U.~G.~Mei\ss{}ner, Electric dipole moments of baryons with bottom quarks
- F. Oosterhof, J. de Vries, R.G.E. Timmermans and U. van Kolck, Nucleon decay in the deuteron
- V. Cirigliano, W. Dekens, J. de Vries, M. Hoferichter and E. Mereghetti, Toward Complete Leading-Order Predictions for Neutrinoless Double $\beta$ Decay
- S. Dreyer, T. Ferber, A. Filimonova, C. Garcia-Cely, C. Hearty, S. Longo, R. Sch\”afer, K. Schmidt-Hoberg, M. Tammaro and K. Trabelsi et al., Physics reach of a long-lived particle detector at Belle II
- R. Fleischer, R. Jaarsma and G. Tetlalmatzi-Xolocotzi, Mapping out the space for new physics with leptonic and semileptonic $B_{(c)}$ decays
- R. Fleischer and E. Malami, Using $B^0_s\to D_s^\mp K^\pm$ Decays as a Portal to New Physics
- M. Beneke, P. B\”oer, G. Finauri and K.K. Vos, QED factorization of two-body non-leptonic and semi-leptonic B to charm decays
- T. Mannel, M. Rahimi and K.K. Vos, Impact of background effects on the inclusive V$_{cb}$ determination
- M. Beneke, P. B\”oer, J.N. Toelstede and K.K. Vos, Light-cone distribution amplitudes of light mesons with QED effects
- T. Binder, A. Filimonova, K. Petraki and G. White, Saha equilibrium for metastable bound states and dark matter freeze-out
- R. Oncala and K. Petraki, Bound states of WIMP dark matter in Higgs-portal models
- Y.P. Wu, E. Pinetti, K. Petraki and J. Silk, Baryogenesis from ultra-slow-roll inflation
- M. Postma, A different perspective on the vev insertion approximation for electroweak baryogenesis
- M. Postma and G. White, Cosmological phase transitions: is effective field theory just a toy?
- P.K. Gupta, T.F.M. Spieksma, P.T.H. Pang, G. Koekoek and C.V. Broeck, Bounding dark charges on binary black holes using gravitational waves
- J.B. Amado, B.C. da Cunha and E. Pallante, QNMs of scalar fields on small Reissner-Nordstrom-AdS_5 black holes
- J. Barrag\’an Amado, B. Carneiro da Cunha and E. Pallante, Remarks on holographic models of the Kerr-AdS$_{5}$ geometry
Outreach:
- For an overview of the outreach and activities in the theory group, follow social media channels (instagram and twitter): https://twitter.com/nikheftheory, https://www.instagram.com/nikheftheorygroup
Visitors:
In view of the coronavirus pandemic, the visitor program has put on hold. We stay in touch with our international colleagues virtually.
Physics Data Processing
Programme Leader
David Groep
Main points: scientific
- Algorithmic improvements to exploit new hardware are nowadays essential, with for instance GPU computing now the chosen solution for the LHCb HLT1 trigger farm, and increased use of such GPUs also in off-line computing – where Nikhef in collaboration with the Netherlands e-Science Center is pursuing new software designs. For the long-term future, Quantum Computing (QC) offers an interesting potential to deal both with the data flows from the HL-LHC, but also with the complex matching algorithms needed in gravitational waves analysis. With the Netherlands already playing a leading role in QC, this line of research is expected to grow based on the collaborations established in 2021.
- FuSE, Fundamental Sciences E-infrastructure, kicked off with large investments for the next phase of the LHC and the SKA ‘science data centre’ prototype in radio-astronomy. There are key changes to the computing and data framework for all three roadmap infrastructures that FuSE supports, which also includes KM3NeT data and compute placement methodology.
- The European Open Science Cloud is taking shape based on the trust and identity concepts, following from one of the main thrusts of the Nikhef group, “Interoperability of trust and identity standards among global infrastructures.” At the same time, Nikhef leads the operational security landscape for EOSC, where data integrity and availability of our science data necessitate new models for information exchange, risk analysis, and global cooperation.
Main points: technical
- The interactive gateway system for the global gravitational waves community (IGWN) was set up at Nikhef, which now drives the major re-consideration of data management and submission frameworks in the community. Through deployment of this apparently simple node, we study the scalability behaviour of computing, and at the same time enable experimentation with a wider range of software deployment paradigms.
- The large-scale 400Gbps infrastructure is being rolled out in production. This complements the 400G testbed service that is part of the SURF Open Innovation Lab at Nikhef, and paves the way for the restart of the LHC data taking.
- On the road to executable papers and reproducible analyses an experimental Jupyter service has been deployed that complements the ‘Stoomboot’ local analysis batch cluster and interactive nodes. Jupyter Notebooks combine the local python environment with software from a range of CVMFS repositories and the ability to document code and algorithms together as one.
- The NDPF Data Processing Facility continued to grow in 2021 with about two PByte of on-line storage and additional processing cores. The ability to host work outside of the Dutch LHC Tier-1 and FuSE, as part of the Dutch National e-Infrastructure coordinated by SURF, also grows to 1200 Terabyte and 1800 compute cores.
- Combining storage and network innovation resulted in a record-setting system boosting over 6 million data operations per second from a single system, using a Fungible DPU (Data Processing Unit) and an IBM Power-9 based system linked together with multiple 100 Gbps links.
- The ARC-CE computing element is now fully handling the compute workload, providing a stable and future-ready interface between global submission systems and the local batch facility – and Nikhef is active in ensuring token-based access to this service.
- Research data management activities continue apace by contributing to the design of the national Thematic Digital Competence Centre programme, emphasizing software sustainability, reproducible processing, and the need for data to ‘remain alive’ through the integration of data management and e-Infrastructure resources, beyond mere data deposition.
Key positions in collaborations
- WLCG Overview Board: Jeff Templon
- Dutch National e-Infrastructure Executive Team: Jeff Templon and David Groep
- European Open Science Cloud, EOSC (Executive Board Architecture WG AAI Task Force, Future Security Operations and Policy): David Groep
Computer codes
- OpenID Connect Federation – Metadata Signing Service, Trust Chain Validation Library
- SimpleSAMLphp – contributions to the OpenID Connect and meta-data discovery components
Main papers in 2021
- Allen: A High-Level Trigger on GPUs for LHCb, R. Aaij et al., Computing and Software for Big Science Vol. 4, Article number: 7 (2020).
- Klaas Wierenga, Leif Johansson, Christos Kanellopoulos, David Groep, Davide Vaghetti, Nicolas Liampotis: EOSC Authentication and Authorization Infrastructure, ISBN 978-92-76-28113-9, doi: 10.2777/8702 (January 2021)
Detector R&D
Programme Leader
Niels van Bakel
Main points: scientific
- The DR&D group, together with the three Nikhef LHC experiments and the Electronics department, works on fast sensors for 4D tracking to achieve order ten picosecond timing (rms) in pixel chips for LHC upgrades and beyond.
- Detailed characterisation of the Timepix4 front-end to understand the total time resolution. This new pixel chip with 80 picosecond time resolution (rms) makes faster timing possible in tracking detectors and X-ray imaging.
- First tracks have been recorded and reconstructed with the Nikhef Timepix4 beam-telescope at the CERN SPS-beamline. The detector layers in the beam-telescope are read out with Nikhef’s SPIDR4 readout system.
- First gain measurement of trench-isolated Low Gain Avalanche Detectors (LGADs). These LGAD detectors can reach tens of picosecond time resolution when sufficient gain is achieved within the sensor layer.
- Monolithic Active Pixel Sensor (MAPS) is a promising technology for fast sensors where readout circuitry is integrated in the sensor array. We performed sub-nanosecond timing measurements with three different monolithic sensor technologies.
Main points: technical
- The two-photon absorption (TPA) setup became fully operational in the DR&D lab. This allows us to study charge collection properties of semiconductor sensors in great detail. First time resolution measurements with this setup have been published (paper by Geertsema).
- Our latest SPIDR4 readout system played a crucial role in testing Timepix4, which resulted in the improved “Timepix4v2” chip, which can be considered the final version of the Timepix4 readout chip.
- The wavefront sensors for the Laser Interferometer Space Antenna (LISA), a detector in space to accurately measure gravitational waves, have been characterized in greater detail: particularly I/V and C/V curves, bandwidth, responsivity, and uniformity. These Indium-Gallium- Arsenide quadrant photodiodes are now selected as baseline sensors for the LISA experiment.
Key positions in collaborations
- Commissioning coordinator Advanced Virgo – Matteo Tacca
- Chair of the wavefront sensing and control work package in the Optics Division of the Einstein Telescope Instrument Science Board – Martin van Beuzekom
- European Community for Future Accelerators (ECFA), Detector R&D Roadmap – Niels van Bakel
- NWO research community Physics for Technology and Instrumentation (PTI) – Niels van Bakel
Awards and funding
- Niels van Bakel, Martin van Beuzekom with NWOi SRON, Photoreceivers for the Laser Interferometer Space Antenna, NWO Open Competition Domain Science-M program.
Main papers in 2021
- K. Heijhoff et al., Timing measurements with a 3D silicon sensor on Timepix3 in a 180 hadron beam, JINST 16 (2021), 08, P08009
- R. Geertsema et al. Charge and temporal characterisation of silicon sensors using a two-photon absorption laser, accepted by JINST 17 (2022) 02, P02023, arXiv 2112.11727
- N. J. S. Bal et al., Medipix3 proton and carbon ion measurements across full energy ranges and at clinical flux rates in MedAustron IR1, December 2021, JINST 16 C12002.
- R. Russo, J. Sonneveld et al., ALICE ITS project: First demonstration of in-beam performance of bent Monolithic Active Pixel Sensors, arXiv. 2105.13000, August 2021