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Base programmes 2022

Theory

Programme Leader

Robert Fleischer

Spectrum of research highlights:

  • R.D. Ball et al., [NNPDF Collaboration], Evidence for intrinsic charm quarks in the proton
  • R. Gomez Ambrosio, J. ter Hoeve, M. Madigan, J. Rojo and V. Sanz, Unbinned multivariate observables for global SMEFT analyses from machine learning
  • R. Abdul Khalek, R. Gauld, T. Giani, E.R. Nocera, T. R. Rabemananjara and J. Rojo,, nNNPDF3.0: evidence for a modified partonic structure in heavy nuclei
  • M. Borinsky, Z. Capatti, E. Laenen and A. Salas-Bernardez, Flow-oriented perturbation theory
  • S. Calo, C. Marinissen and R. Rahn, Discrete symmetries and efficient counting of operators
  • M. Bochicchio and E. Pallante, Low-energy theorem and OPE in the conformal window of massless QCD
  • P. Cal, J. Thaler and W.J. Waalewijn, Power counting energy flow polynomials
  •  Y.T. Chien, R. Rahn, D.Y. Shao, W.J. Waalewijn and B. Wu, Precision boson-jet azimuthal decorrelation at hadron colliders
  • M. Jaarsma, Y. Li, I. Moult, W. Waalewijn and H.X. Zhu, Renormalization group flows for track function moments
  • S. Bruggisser, D. van Dyk and S. Westhoff, Resolving the flavor structure in the MFV-SMEFT
  • M. Beneke, P. Boer, J.N. Toelstede and K.~K.~Vos, Light-cone distribution amplitudes of heavy mesons with QED effects
  • M. Fael, M. Rahimi and K.K. Vos, New physics contributions to moments of inclusive b→c semileptonic decays
  • F. Bernlochner, M. Fael, K. Olschewsky, E. Persson, R. van Tonder, K.K. Vos and M. Welsch, First extraction of inclusive V_{cb} from q^2 moments
  • K. De Bruyn, R. Fleischer, E. Malami and P. van Vliet, New Physics in B^0_q−B^0_q_bar mixing: present challenges, prospects, and implications for B^0_q→μ+μ−
  • R. Fleischer, R. Jaarsma and K.K. Vos, Zooming into CP violation in B(s)→hh decays
  • R. Fleischer, E. Malami, A. Rehult and K.K. Vos, Fingerprinting CP-violating New Physics with B→Kμ+μ−
  • M. Rahimi and K.K. Vos, Standard Model predictions for lepton flavour universality ratios of inclusive semileptonic B decays
  • J. de Vries et al., Light sterile neutrinos, left-right symmetry, and 0νββ decay
  • V. Cirigliano, J. de Vries, L. Hayen, E. Mereghetti and A. Walker-Loud, Pion-induced radiative corrections to neutron β decay
  • W. Dekens, J. de Vries and S. Shain, CP-violating axion interactions in effective field theory
  • A. Filimonova, S. Junius, L. Lopez Honorez and S. Westhoff, Inelastic Dirac dark matter
  • T. Binder, A. Filimonova, K. Petraki and G. White, Saha equilibrium for metastable bound states and dark matter freeze-out
  • T. Ferber, A. Filimonova, R. Schafer and S.~Westhoff, Displaced or invisible? ALPs from B decays at Belle II
  • M. Postma, J. van de Vis and G. White, Resummation and cancellation of the VIA source in electroweak baryogenesis
  • J.J. Postema, P. Bonizzi, G. Koekoek, R.L. Westra and S.J.J.M.F. Kokkelmans, Hybrid quantum singular spectrum decomposition for time series analysis

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

Special Event:

Bert Schellekens Fest on the occasion of the retirement of Prof. Dr. Bert Schellekens (Organizers Beatriz Gato Rivera and Robert Fleischer): https://indico.nikhef.nl/event/2688/

Physics Data Processing

Programme Leader

David Groep

Main points: scientific

  • The LHCb HLT1 trigger system based on Allen was put in place entirely in 2022, ready for data taking in the begging of the subsequent year. This leverages the algorithmic improvements made with GPU computing, which is now the chosen solution for the LHCb HLT1 trigger farm. The group strengthened the use of GPUs also in off-line computing – with additional postdoctoral staff assigned to the collaboration with the Netherlands e-Science Center on such new software designs. The Quantum Computing (QC) algorithm workshops proceeded apace, with joint Nikhef-SURF activities in LHCb track finding using quantum algorithms.
  • FuSE, Fundamental Sciences E-infrastructure, provides the basis for 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. In collaboration with the KM3NeT activities around computing that are increasingly centred at Nikhef, the PDP programme explores more cross-institutional use of data orchestration (Rucio) and workflow management systems (DIRAC) – building on both SURF and EGI offerings in these areas.
  • The central role of trust and identity services in both WLCG, national infrastructures (SRAM) and in the European Open Science Cloud, drives the work to apply complementary assurance and security techniques for community management that were hitherto primarily applied to pure identity authentication systems. AARC guidelines on secure operation of attribute authorities has been investiogated, including its applicability to the new ‘token-based’ authentication and authorization infrastructures (AAI) that are emerging for WLCG, IGWN, and the use of non-web services (in particular interactive command-line access to HPC and HTC systems). At the same time, Nikhef continues to lead 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

  • In preparation for the HL-LHC data flows Nikhef, SURF, and Nokia together deployed an 800 Gbps text facility (and officially launched in January 2023). This complements the 400G testbed service that is part of the SURF Open Innovation Lab at Nikhef, and paves the way for the next generation data flows.
  • Research and development in collaboration with Delft Technical University and 4TU Research Data resulted in a prototype institutional data management platform based on the open source Djehuty software. The Nikhef instance specifically targeting voluminous data sets, linking FAIR data repositories and the local analysis facility storage services based on dCache was evaluated (for moving into production in 2023)
  • The NDPF Data Processing Facility continued to grow in 2022 with about six 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 1800 Terabyte and 1800 compute cores.
  • 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.
  • Nikhef innovation experts co-designed the Dutch national supercomputer ‘Snellius’ and joined the procurement team. This showed specific benefits also for more throughput oriented cases, since this new HPC system also has capability ‘islands’ tuned to big data processing – such that it will support better use of joint HPC and HTC workflows, for example for GW template generation and analysis.

Key positions in collaborations

  • WLCG Overview Board: Jeff Templon
  • Dutch National e-Infrastructure Executive Team: Jeff Templon and David Groep
  • NWO Thematic Digital Competence Centre Lead: David Groep
  • European Open Science Cloud, EOSC (Executive Board Architecture WG AAI Task Force, Future Security Operations and Policy): David Groep

Computer codes

Main papers in 2022

  • Roel Aaij et al. A Comparison of CPU and GPU Implementations for the LHCb Experiment Run 3 Trigger,  Computing and Software for Big Science 6 (2022) 1
  • Groep, David Leo, Collier, Ian, Dack, Tom, Jensen, Jens, Kelsey, David, Kremers, Maarten, Neilson, Ian, Paetow, Stefan, Short, Hannah, Sallé, Mischa, & Stevanovic, Uros. (2022). Guidelines for Secure Operation of Attribute Authorities and issuers of statements for entities. Zenodo.

Detector R&D

Programme Leader

Niels van Bakel

Main points: scientific

  • demonstrated operation at +20 C and a detection efficiency of 99% for a digital pixel test structure MAPS irradiated with a dose of 1015 1 MeV neq/cm2 the ALICE pixel detector upgrade
  • demonstrated sub-nanosecond timing (300 ps) in 4×4 pixel matrix for high voltage CMOS MAPS
  • 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

  • First tracks with complete 8-layer Timepix4 telescope + SPIDR4
  • First time resolution measurements of trench-isolated low gain avalanche detectors
  • (almost) complete characterisation of LISA QPD.
  • New batch SPIDR4 boards; start of delivery to the collaboration.
  • Master thesis on muon tomography.
  • Expanding lab with new single photon absorption laser.
  • 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 to be 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

  • FASTER – Novel ultra-precise picosecond detectors and algorithms for particle detectors, NWO Open Competition Domain Science – XL, Round 2021-2022

Main papers in 2022

  • Heijhoff, K. and Akiba, K. and Ballabriga, R. and van Beuzekom, M. and Campbell, M. and Colijn, A. P. and Fransen, M. and Geertsema, R. and Gromov, V. and Cudie, X. Llopart, Timing performance of the Timepix4 front-end, JINST 17 (2022), 07, P07006
  • G. Aglieri Rinella et al, R. Russo & J. Sonneveld, Digital Pixel Test Structures implemented in a 65 nm CMOS process, 10.48550/arXiv.2212.08621