* Particle Physics

ATLAS

Wouter Verkerke, Nicolo de Groot

Observation of Higgs boson production in association with a top quark pairs
Observation of Higgs boson decay to pairs of b-quarks
News article in Nature on the general search strategy interviewing Sascha Caron
A new strategy has been developed to study polarized single top quark production (jointly with the Nikhef theory group)
New stringent limits set on lepton flavor violation in Z boson decays

A record luminosity of 158 fb^–1 has been delivered to the ATLAS detector at the end of LHC run-2
The silicon-strip end-cap detector that will be assembled at Nikhef in the coming years has passed the final design review
The hardware for the ATLAS phase-1 deployment of the FELIX Trigger and DAQ system is entering the production phase
Tristan du Pree takes over muon project leadership from Gerjan Bobbink

Observation of Higgs boson production in association with a top quark pair at the LHC with the ATLAS detector, Phys. Lett. B 784 (2018) 173
Observation of H→bb̅ decays and VH production with the ATLAS detector, Phys. Lett. B 786 (2018) 59
A search for lepton-flavor-violating decays of the Z boson into a tau-lepton and a light lepton with the ATLAS detector, Phys. Rev. D 98 (2018) 092010
Effective operators in t-channel single top production and decay, Eur.Phys.J. C78 (2018) no.11, 919

Marcel Merk

Decay-time dependent CP violation studies: the study of the mixing phase φ_s of B⁰oscillations using B_s→ J/ψ φ decays and the decay phase γ using B_s>D_sK decays.
Precise measurement of very rare decays of B⁰_s→μ⁺μ^– including the effective lifetime of this decay. Subsequently, the first observation of B⁰→μμ and the relative branching ratio of B⁰ over B_s 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

Completion of the mass production and quality assurance of Velo upgrade detector modules and the manufacturing of two sets of vacuum encapsulation boxes for the detector.
Deinstallation of the VELO- 1vertex detector, the cooling and preparation for the installation of the upgraded detector.
Completion of the production of ColdBox-es for the Scintillating Fibar 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.

LHCb, Physics case for an LHCb Upgrade II – Opportunities in flavour physics, and beyond, in the HL-LHC era, arXiv:1808.08865.
LHCb, Measurement of the CKM angle γ using B^±→ DK^± with D→ K_S⁰π⁺π^–, K_S⁰ K⁺K^– decays, DOI 10.1007/JHEP08(2018)176.
LHCb, Observation of a new Ξ_b^– resonance, DOI:10.1103/PhysRevLett.121.072002.
Bel, S.Esen, N. Tuning, M. Merk et al., Measurement of CP asymmetry in B_s⁰→ D_s^*∓ K^± decays, DOI 10.1007/JHEP03(2018)059.

Raimond Snellings

Energy dependence and fluctuations of anisotropic flow in Pb-Pb collisions at √s_NN =5.02 and 2.76 TeV, ALICE collaboration, J. High Energ. Phys. (2018) 2018: 103. https://doi.org/10.1007/JHEP07(2018)103
Measurement of D⁰, D⁺, D^*+ and D⁺_s production in Pb-Pb collisions at √s_NN =5.02 TeV, J. High Energy Phys. 10 (2018) 174 , https://doi.org/10.1007/JHEP10%282018%29174
Neutral pion and η meson production in p-Pb collisions at √s_NN = 5.02 TeV, Eur. Phys. J. C 78 (2018) 624 , https://doi.org/10.1140/epjc/s10052-018-6013-8

Steven Hoekstra

Studied and determined key properties of the BaF electronic structure (energies, lifetimes, branching ratios) with implications for molecular laser cooling
Calculated the hyperfine constants and the effective electric field in BaF
Optimized the properties of a cryogenic beam of SrF molecules
Obtained a complete set of SrF deceleration data and analyzed them by a careful comparison to numerical trajectory simulations, characterizing the stability in the deceleration process

A prototype transformer for the high-voltage upgrade of the molecule decelerator is being tested
A cryogenic buffer gas source for slow molecular beam has been constructed and is operational
The interaction zone of the electron-EDM experiment has been designed, and first prototypes are being constructed
An intense supersonic source of BaF molecules has become operational, and first measurements on molecular properties are underway.

Measuring the electric dipole moment of the electron in BaF – The NL-eEDM collaboration, Aggarwal, P., Bethlem, H.L. et al. Eur. Phys. J. D (2018) 72: 197. https://doi.org/10.1140/epjd/e2018-90192-9