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Particle Physics 2022

ATLAS

Programme Leaders

Wouter Verkerke, Frank Filthaut, Ivo van Vulpen (deputy)

Main points: scientific

  • New combined interpretation of single and double Higgs boson production in terms of the Higgs boson self-coupling.
  • A first measurement of the Higgs boson width (lifetime) using off-shell Higgs production in the ZZ4l and ZZ2l2 decay channels.
  • In the area of top quark physics a first observation was published of the simultaneous production of 4 top quarks (tttt). This process, with a tiny SM cross-section, is highly sensitive to the effects of a broad array of new physics theories.

Main points: technical

  • The FELIX Trigger and readout system, co-developed at Nikhef,has been used for the commissioning efforts of the newly installed detectors, notably the muon New Small Wheel and the upgraded Level-1 calorimeter trigger. A first candidate FELIX card for the next (Phase-2) upgrade has been built and its suitability is being evaluated.
  • The upgrade of the ATLAS Inner Tracker (ITk) focuses mostly on global mechanical structures. The first of the two end-cap structures has been produced, apart from minor rework; and the tooling for the strip detector petal insertion and the thermal enclosure have been determined (in collaboration with DESY).
  • Suitable Low-Gain Avalanche Diode (LGAD) designs for the ATLAS High-Granularity Timing Detector (HGTD) have been identified, and a possibly final readout ASIC has been designed. FELIX based readout has been established of several readout ASICs.

Awards, fellowships etc.

  • ATLAS Thesis Prize (Brian Moser)
  • Springer Thesis Award (Brian Moser)
  • ENW-XL FASTER grant (shared with R&D, LHCb, and ALICE)

Key positions in collaborations

  • Physics coordinator: Pamela Ferrari
  • Authorship committee chair: Frank Filthaut
  • Collaboration Board Chairperson Advisory Group member: Wouter Verkerke
  • Statistics committee: Lydia Brenner, Wouter Verkerke
  • Exotics group convener: Flavia Dias
  • Early Career Scientist Board: Flavia Dias
  • Diversity and Inclusion contact: Clara Nellist
  • Convener of top-quark mass & properties subgroup: Clara Nellist
  • ITk system engineer & global structures coordinator: Marcel Vreeswijk
  • FELIX firmware coordinator: Frans Schreuder
  • FELIX software coordinator: Mark Dönszelmann
  • HGTD DAQ/Luminosity/DCS coordinator: Mengqing Wu
  • HGTD Institute Board chairperson: Frank Filthaut

Main papers in 2022

  • “A detailed map of Higgs boson interactions by the ATLAS experiment ten years after the discovery”, ATLAS Collaboration, Nature 607 (2022) 52
  • “Constraining the Higgs boson self-coupling from single- and double-Higgs production with the ATLAS detector using pp collisions at s = 13 TeV”,ATLAS Collaboration, arXiv:2211.01216
  • “Search for off-shell Higgs production and constraints on the total width of the Higgs boson in the ZZ4l and ZZ2l2 decay channels with the ATLAS detector”, ATLAS Collaboration, ATLAS-CONF-2022-068

LHCb

Programme Leader

Marcel Merk, Mara Soares (deputy)

Main points: scientific

  • High precision measurement of the Bs – anti-Bs meson oscillation frequency using decays of the type Bs → Ds pi.
  • Decay-time dependent CP violation studies: the study of the mixing phase φs of Bs0 oscillations using Bs→ J/ψ φ decays and the decay phase γ using Bs → DsK decays.
  • Precise measurement of very rare decays of B0s→μ+μ– including the effective lifetime of this decay. Subsequently, the search for B0→μμ and the relative branching ratio of B0 over Bs for these decays. Furthermore, the search for the even stronger suppressed decays involving electrons and tau leptons: B0(s)→ e+e–, Bc → τν, and of the Lepton Flavor violating decays B0(s)→ e μ.
  • Lepton universality tests in semileptonic b-quark to s-quark decays probing physics beyond the standard model, in particular using the angular distribution variables.
  • Searches for long-lived massive particles through signals of displaced as well as emerging jets

Main points: technical

  • Production of Velo upgrade detector modules and the installation of two sets of vacuum encapsulation boxes for the detector.
  • Installation of Scintillating Fiber detector modules, the Coldboxes and the cooling infrastructure.
  • Commissioning of SciFi modules in the C-frames at CERN.
  • Development and commissioning of the real-time reconstruction framework and implementation of reconstruction algorithms.

Awards, fellowships etc.

  • Vici: Niels Tuning and Wouter Hulsbergen,
  • Swiss SNF mobility grant, Andrea Mauri,
  • Veni: Andrii Usachov, Jacco de Vries, Suzanne Klaver
  • CERN scientific associate: Gerhard Raven

Key positions in collaborations

  • Physics Coordinator: Niels Tuning
  • Run Coordinator: Niels Tuning,
  • Velo Deputy project leader: Kazu Akiba,
  • SciFi deputy project leader: Antonio Pellegrino,
  • Data Processing and Analysis deputy project leader: Patrick Koppenburg
  • Membership Committee chair: Marcel Merk,
  • Working group convenor of B to CC decays: Miriam Lucio Martinez
  • Working group convenor B to Open Charm Time Dependent: Emmy Gabriel
  • Working group convenor Very rare decays: Mick Mulder
  • Real Time Analysis deputy project leader: Gerhard Raven
  • Speakers Bureau deputy chair: Keri Vos
  • SciFi controls and monitor convenor: Kazu Akiba

Main papers in 2022

  • Measurement of the lepton universality parameters in B+ → K+ l+l- and B0 → K*)l+l-  decays, submitted to Phys Rev D,  arXiv:2212.09153
  • Test of lepton universality in b → s l+ l- decays, Phys Rev Lett., arXiv:2212.09152
  • Observation of a J/psi \Lambda resonance consistent with a strange pentaquark candidate in B → J/\pis \Lambda p decays, Phys Rev Lett., arXiv:2210.10346
  • Direct CP violation in charmless three-body decays of B+ mesons, Phys Rev D , arXiv:2206.07622
  • Observation of the double charmed baryon decay \Xicc++ → \Xi’c+ pi+, JHEP 05 (2022) 038.
  • Observation of the decay \Lambda B0 → \Lambda C+ tau nu, Phys. Rev. Lett. 128 (2022)

ALICE

Programme Leader

Raimond Snellings, Marta Verweij (deputy)

Main points: scientific

  • Measurements of transport properties of Quark Gluon Plasma
  • Constraints on magnitude chiral magnetic effect
  • Charm baryon and meson cross-sections as function of multiplicity in proton-proton collisions

Main points: technical

  • Installation of the upgrade of inner-tracking system at CERN, commissioning and first data taking.
  • Research and development for 4D tracking technology for ITS3 (run 3+4) and ALICE3 (run 5)

Key positions in collaborations

  • Elected Spokesperson : M. van Leeuwen
  • Upgrade coordinator : M. van Leeuwen
  • Physics Working Group Convenor: M. Verweij
  • System Run Coordinator: I. Ravasenga
  • Conference Committee: A. Grelli
  • Editorial Board: P. Christakoglou, T. Peitzmann

Awards, fellowships etc.

  • Vici: Marco van Leeuwen
  • Start-up: Marta Verweij

Main papers in 2022

  • The ALICE Collaboration. Measurement of anti-3He nuclei absorption in matter and impact on their propagation in the Galaxy. Nat. Phys. 19, 61–71 (2023). 10.1038/s41567-022-01804-8
  • Measurement of the Groomed Jet Radius and Momentum Splitting Fraction in pp and Pb-Pb Collisions at 5.02 TeV. S. Acharya et al. (A Large Ion Collider Experiment Collaboration) Phys. Rev. Lett. 128, 102001 – Published 7 March 2022
  • The Alice Collaboration. Direct observation of the dead-cone effect in quantum chromodynamics. Nature 605 (2022) 7910, 440-446, Nature 607 (2022) 7920, E22 (erratum).  10.1038/s41586-022-04572-w, 10.1038/s41586-022-05026-z
  • First demonstration of in-beam performance of bent Monolithic Active Pixel Sensors, Nucl.Instrum.Meth.A 1028 (2022) 166280,  10.1016/j.nima.2021.166280

eEDM

Programme Leader

Steven Hoekstra

Main points: scientific

  • Accurate analysis of the hyperfine structure in the X2Sigma and A2Pi state of BaF
  • Demonstrated all-optical spin-precession method for sensitive eEDM searches
  • Two-step detection scheme to characterise molecular beam properties developed

Main points: technical

  • Developed method to analyse BaF cryogenic beam properties using CCD images
  • Sideband creation for BaF laser cooling using AOMs completed

Awards, fellowships etc.

  • VICI Steven Hoekstra

Main papers in 2022

  • Benchmarking of the Fock-space coupled-cluster method and uncertainty estimation: Magnetic hyperfine interaction in the excited state of BaF, The NL-eEDM collaboration:, Malika Denis, Pi A B Haase, Maarten C Mooij, Yuly Chamorro, Parul Aggarwal, Hendrick L Bethlem, Alexander Boeschoten, Anastasia Borschevsky, Kevin Esajas, Yongliang Hao, Steven Hoekstra, Joost W F van Hofslot, Virginia R Marshall, Thomas B Meijknecht, Rob G E Timmermans, Anno Touwen, Wim Ubachs, Lorenz Willmann, Yanning Yin, Physical Review A, vol. 105(5), 052811 (2022)
  • Molecular enhancement factors for the P,T-violating electric dipole moment of the electron in BaCH_3 and YbCH_3 symmetric top molecules, Yuly Chamorro, Anastasia Borschevsky, Ephraim Eliav, Nicholas R. Hutzler, Steven Hoekstra, Lukas F. Pasteka, Phys. Rev. A, vol. 106(5), 052811 (2022)