Particle Physics 2019

ATLAS

Programme Leaders

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

Main points: scientific

  • New constraints on Higgs decays to 2nd generation leptons using the full Run-2 data.
  • First constraints on Higgs self-couplings obtained from the combined interpretation of single Higgs decay and di-Higgs decays.
  • New measurement of Higgs couplings from the combined interpretation of observed h(125) Higgs decays in Run-2 data.
  • The first ATLAS ‘general search’ paper was published
  • New more stringent limits on 3rd generation lepto-quarks from run-2 data

Main points: technical

  • The silicon-strip end-cap detector that will be assembled at Nikhef in the coming years has passed the pre-production readiness review
  • The hardware for the ATLAS phase-1 deployment of the FELIX Trigger and DAQ system is now in full production
  • A new RasNik alignment system for the new ‘BIS’ muon chambers that will be installed in ATLAS in 2025 has been designed and prototyped at Nikhef, and is now entering the production phase

Awards, fellowships etc.

  • RU Excellence fellowship: Clara Nellist

Key positions in collaborations

  • Coordinators B-physics, Muon trigger: Olya Igonkina, Marcus Morgenstern, resp.
  • FELIX firmware coordinator: Frans Schreuder
  • FELIX software coordinator: Mark Dönszelmann
  • FELIX user support coordinator: Nikolina Ilic
  • ITk endcap structures activity coordinator & ITk system engineer: Marcel Vreeswijk
  • Deputy publications committee chair: Pamela Ferrari
  • Publication committee & Authorship committee: Frank Filthaut
  • H→bb/cc physics sugroup convener: Hannah Arnold
  • Statistics committee: Wouter Verkerke

Main papers in 2019

  • Combined measurements of Higgs boson production and decay using up to 80 fb−1 of
    proton-proton collision data at √s=13 TeV collected with the ATLAS experiment, Phys. Rev. D 101 (2020) 012002
  • Searches for third-generation scalar leptoquarks in √s=13 TeV pp collisions with the ATLAS detector, JHEP 06 (2019) 144
  • A strategy for a general search for new phenomena using data-derived signal regions and its application within the ATLAS experiment, Eur. Phys. J. C 79 (2019) 120

LHCb

Programme Leader

Marcel Merk,

Main points: scientific

  • 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 first observation of B0→μμ and the relative branching ratio of B0 over Bs for these decays. Furthermore, the search for the even stronger suppressed decays B0(s)→ e+e– 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,
  • Searches for long-lived massive particles through signals of displaced as well as emerging jets

Main points: technical

  • Completion of the production and quality assurance of Velo upgrade detector modules and the manifacturing of two sets of vacuum encapsulation boxes for the detector.
  • Deinstallation of the VELO-1 vertex detector, the cooling and preparation for the installation of the upgraded detector.
  • Completion of the production of ColdBox-es for the Scintillating Fiber detector.
  • Installation and testing 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, Maxime Schgubiger,
  • Marie Curie Fellowship: Suzanne Klaver,
  • LHCb Thesis prize: Jacco de Vries,
  • LHCb industry award for 3D systems company through collaboration with Antonio Pellegrino,
  • Welcome of Maastricht University in the LHCb collaboration.

Key positions in collaborations

  • Editorial Board Chair: Patrick Koppenburg,
  • Outer Tracker project leader: Niels Tuning,
  • Velo Deputy project leader: Kazu Akiba,
  • SciFi deputy project leader: Antonio Pellegrino,
  • Real Time Analysis Institute Board chair: Marcel Merk,
  • Working group convenor of B to CC decays: Sevda Esen,
  • Working group convenor of rare decays: Flavio Archilli,
  • Stripping coordinator: Carlos Vazquez Sierra.

Main papers in 2019

  • LHCb, Observation of CP Violation in Charm Decays, Phys.Rev.Lett. 122 (2019) 211803.
  • LHCb, Search for lepton-universality violation in B+ –>K+ l+ l- decays, Phys.Rev.Lett 122 (2019) 191801.
  • LHCb, Updated measurement of time-dependent CP-voilating observables  in Bs→ J/ψ L+ K- decays,  Eur.Phys.J.C. 79 (2019) 706.
  • LHCb, Test of lepton universality with Λb0 → p K- l+ l- decays, arXiv:1912.08139.
  • LHCb, Measurement of the Bs→φφ decay and search for the B0 → φφ decay, JHEP 12 (2019) 155.

ALICE

Programme Leader

Raimond Snellings, Marta Verweij

Main points: scientific

  • Measurements of transport properties of Quark Gluon Plasma
  • Constraints on magnitude chiral magnetic effect

Main points: technical

  • Upgrade of ITS completed and all staves shipped to CERN

Key positions in collaborations

  • Physics coordinator : M. van Leeuwen
  • Project leader ITS: Paul Kuijer
  • Physics Working Group Convenors: A. Grelli
  • Physics Analysis Group Coordinators: B. Trzeciak, D. Caffari
  • Conference Committee: P. Christakoglou, M. Verweij
  • Editorial Board: P. Christakoglou

Awards, fellowships etc.

  • Vici: M. van Leeuwen
  • START-UP grant: M. Verweij
  • Westerdijk fellowship (UU): M. Verweij
  • Veni: A. Dubla

Main papers in 2019

  • Direct photon elliptic flow in Pb-Pb collisions at √sNN = 2.76 TeV, Phys. Lett. B 789 (2019) 308
  • Λc+ production in Pb-Pb collisions at √sNN = 5.02 TeV, Phys. Lett. B 793 (2019) 212
  • Measurement of the production of charm jets tagged with D0 mesons in pp collisions at √s = 7 TeV, J. High Energy Phys. 08 (2019) 133
  • Measurement of prompt D0, D+, D*+, and D+s production in p-Pb collisions at √sNN = 5.02 TeV, J. High Energy Phys. 12 (2019) 092

eEDM

Programme Leader

Steven Hoekstra

Main points:

  • Molecular spectroscopy and structure: theory & experiment (2 papers).
  • Dedicated cryogenic source has been coupled to decelerator. Decelerator is working in either guiding or deceleration mode.
  • Setting up a fast-beam EDM measurement.

Main papers in 2019

  • J. O. Grasdijk, X. F. Bai, I. Engin (et al.), Electro-optic sensor for static fields, Applied Physics B 125 (2019)212
  • Y. Hao, L. Visscher, S. Hoekstra (et al.), High accuracy theoretical investigations of CaF, SrF, and BaF and implications for laser-cooling, The Journal of Chemical Physics 151 (2019)34302