P. Van Mechelen
A5012308313- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Cosmology and Gravitation Theories
- Computational Physics and Python Applications
- Neutrino Physics Research
- Radiation Detection and Scintillator Technologies
- Medical Imaging Techniques and Applications
- Astrophysics and Cosmic Phenomena
- Black Holes and Theoretical Physics
- Particle Accelerators and Free-Electron Lasers
- Distributed and Parallel Computing Systems
- Radiation Therapy and Dosimetry
- Gamma-ray bursts and supernovae
- Cold Atom Physics and Bose-Einstein Condensates
- International Science and Diplomacy
- Nuclear reactor physics and engineering
- Atomic and Subatomic Physics Research
- Superconducting Materials and Applications
- Big Data Technologies and Applications
- Optical properties and cooling technologies in crystalline materials
- CCD and CMOS Imaging Sensors
- Radioactivity and Radon Measurements
University of Antwerp
2016-2025
Institute of High Energy Physics
2020-2024
A. Alikhanyan National Laboratory
2022-2024
Vrije Universiteit Brussel
2023
Interuniversity Institute for High Energies
2012-2022
Marmara University
2019
Kafkas University
2019
European Organization for Nuclear Research
2013-2014
UCLouvain
2013
Fermi National Accelerator Laboratory
2013
Results are presented from searches for the standard model Higgs boson in proton-proton collisions at sqrt(s) = 7 and 8 TeV Compact Muon Solenoid experiment LHC, using data samples corresponding to integrated luminosities of up 5.1 inverse femtobarns 5.3 TeV. The search is performed five decay modes: gamma gamma, ZZ, WW, tau tau, b b-bar. An excess events observed above expected background, with a local significance 5.0 deviations, mass near 125 GeV, signalling production new particle. that...
The CMS apparatus was identified, a few years before the start of LHC operation at CERN, to feature properties well suited particle-flow (PF) reconstruction: highly-segmented tracker, fine-grained electromagnetic calorimeter, hermetic hadron strong magnetic field, and an excellent muon spectrometer. A fully-fledged PF reconstruction algorithm tuned detector therefore developed has been consistently used in physics analyses for first time collider. For each collision, comprehensive list...
This paper describes the CMS trigger system and its performance during Run 1 of LHC. The consists two levels designed to select events potential physics interest from a GHz (MHz) interaction rate proton-proton (heavy ion) collisions. first level is implemented in hardware, selects containing detector signals consistent with an electron, photon, muon, τ lepton, jet, or missing transverse energy. A programmable menu up 128 object-based algorithms used for subsequent processing. thresholds are...
Properties of the Higgs boson with mass near 125 $$\,\text {GeV}$$ are measured in proton-proton collisions CMS experiment at LHC. Comprehensive sets production and decay measurements combined. The channels include $$\gamma \gamma $$ , $$\mathrm{Z}\mathrm{Z}$$ $$\mathrm{W}\mathrm{W}$$ $$\tau \tau $$\mathrm{b} \mathrm{b} $$\mu \mu pairs. data samples were collected 2011 2012 correspond to integrated luminosities up 5.1 {fb}^\text {-1}$$ 7 {TeV}$$ 19.7 8 . From high-resolution channels, is...
A detailed description is reported of the analysis used by CMS Collaboration in search for standard model Higgs boson pp collisions at LHC, which led to observation a new boson. The data sample corresponds integrated luminosities up 5.1 inverse femtobarns sqrt(s) = 7 TeV, and 5.3 8 TeV. results five decay modes gamma gamma, ZZ, WW, tau tau, bb, show combined local significance 5 deviations near 125 GeV, are reviewed. fit invariant mass two high resolution channels, ZZ 4 ell, gives estimate...
New sets of parameters (“tunes”) for the underlying-event (UE) modelling pythia8, pythia6 and herwig++ Monte Carlo event generators are constructed using different parton distribution functions. Combined fits to CMS UE proton–proton ( $$\mathrm {p}\mathrm {p}$$ ) data at $$\sqrt{s} = 7\,\text {TeV} $$ proton–antiproton {p}\overline{\mathrm{p}} from CDF experiment lower $$\sqrt{s}$$ , used study models constrain their parameters, providing thereby improved predictions collisions 13 $$\,\text...
Improved jet energy scale corrections, based on a data sample corresponding to an integrated luminosity of 19.7 inverse-femtobarns collected by the CMS experiment in proton-proton collisions at center-of-mass 8 TeV, are presented. The corrections as function pseudorapidity eta and transverse momentum pT extracted from simulated events combining several channels methods. They account successively for effects pileup, uniformity detector response, residual data-simulation differences. Further...
Observation of the diphoton decay mode recently discovered Higgs boson and measurement some its properties are reported. The analysis uses entire dataset collected by CMS experiment in proton-proton collisions during 2011 2012 LHC running periods. data samples correspond to integrated luminosities 5.1[Formula: see text]at [Formula: text] 19.7[Formula: 8[Formula: . A clear signal is observed channel at a mass close 125[Formula: with local significance text], where expected for standard model...
The CMS muon detector system, reconstruction software, and high-level trigger underwent significant changes in 2013-2014 preparation for running at higher LHC collision energy instantaneous luminosity. performance of the modified system is studied using proton-proton data center-of-mass $\sqrt{s}=$ 13 TeV, collected 2015 2016. measured parameters, including spatial resolution, efficiency, timing, are found to meet all design specifications well reproduced by simulation. Despite more...
Results are presented from a search for particle dark matter (DM), extra dimensions, and unparticles using events containing jet an imbalance in transverse momentum. The data were collected by the CMS detector proton-proton collisions at LHC correspond to integrated luminosity of 19.7 inverse femtobarns centre-of-mass energy 8 TeV. number observed is found be consistent with standard model prediction. Limits placed on DM-nucleon scattering cross section as function DM mass spin-dependent...
Measurements of two- and multi-particle angular correlations in pp collisions at sqrt(s) = 5, 7, 13 TeV are presented as a function charged-particle multiplicity. The data, corresponding to integrated luminosities 1.0 inverse picobarn (5 TeV), 6.2 picobarns (7 0.7 (13 were collected using the CMS detector LHC. second-order (v[2]) third-order (v[3]) azimuthal anisotropy harmonics unidentified charged particles, well v[2] K0 short Lambda/anti-Lambda extracted from long-range two-particle...
New sets of CMS underlying-event parameters ("tunes") are presented for the PYTHIA8 event generator. These tunes use NNPDF3.1 parton distribution functions (PDFs) at leading (LO), next-to-leading (NLO), or next-to-next-to-leading (NNLO) orders in perturbative quantum chromodynamics, and strong coupling evolution LO NLO. Measurements charged-particle multiplicity transverse momentum densities various hadron collision energies fit simultaneously to determine tunes. Comparisons predictions new...
The study of the spin-parity and tensor structure interactions recently discovered Higgs boson is performed using H to ZZ, Z gamma*, gamma* 4 l, WW l nu nu, gamma decay modes. full dataset recorded by CMS experiment during LHC Run 1 used, corresponding an integrated luminosity up 5.1 inverse femtobarns at a center-of-mass energy 7 TeV 19.7 8 TeV. A wide range spin-two models excluded 99% confidence level or higher, 99.87% for minimal gravity-like couplings, regardless whether assumptions are...
Results are presented from a search for the rare decays ${B}_{s}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ and ${B}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ in $pp$ collisions at $\sqrt{s}=7$ 8 TeV, with data samples corresponding to integrated luminosities of 5 $20\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$, respectively, collected by CMS experiment LHC. An unbinned maximum-likelihood fit dimuon...
A search for new physics is performed in multijet events with large missing transverse momentum produced proton-proton collisions at sqrt(s) = 8 TeV using a data sample corresponding to an integrated luminosity of 19.5 inverse femtobarns collected the CMS detector LHC. The divided into three jet multiplicity categories (3-5, 6-7, and or more jets), studied further bins two variables: scalar sum momenta momentum. observed numbers various are consistent backgrounds expected from standard model...
In July 2012, the ATLAS and CMS collaborations at CERN Large Hadron Collider announced observation of a Higgs boson mass around 125 gigaelectronvolts. Ten years later, with data corresponding to production 30-times larger number bosons, we have learnt much more about properties boson. The experiment has observed in numerous fermionic bosonic decay channels, established its spin-parity quantum numbers, determined measured cross-sections various modes. Here Collaboration reports most...
This paper presents a search for the pair production of top squarks in events with single isolated electron or muon, jets, large missing transverse momentum, and mass. The data sample corresponds to an integrated luminosity 19.5 inverse femtobarns pp collisions collected 2012 by CMS experiment at LHC center-of-mass energy sqrt(s) = 8 TeV. No significant excess is observed above expectation from standard model processes. results are interpreted context supersymmetric models that decay either...
Searches for the direct electroweak production of supersymmetric charginos, neutralinos, and sleptons in a variety signatures with leptons $$\mathrm{W}$$ , $$\mathrm{Z}$$ Higgs bosons are presented. Results based on sample proton-proton collision data collected at center-of-mass energy $$\sqrt{s}=8\,\mathrm{TeV}$$ CMS detector 2012, corresponding to an integrated luminosity 19.5 $$\,\text {fb}^\text {-1}$$ . The observed event rates agreement expectations from standard model. These results...
A search for a standard model Higgs boson decaying into pair of τ leptons is performed using events recorded by the CMS experiment at LHC in 2011 and 2012. The dataset corresponds to an integrated luminosity 4.9 fb−1 centre-of-mass energy 7 TeV 19.7 8 TeV. Each lepton decays hadronically or leptonically electron muon, leading six different final states -lepton pair, all considered this analysis. An excess observed over expected background contributions, with local significance larger than 3...
A search for the standard model Higgs boson ($H$) decaying to $b\overline{b}$ when produced in association with a weak vector ($V$) is reported following channels: $W(\ensuremath{\mu}\ensuremath{\nu})H$, $W(e\ensuremath{\nu})H$, $W(\ensuremath{\tau}\ensuremath{\nu})H$, $Z(\ensuremath{\mu}\ensuremath{\mu})H$, $Z(ee)H$, and $Z(\ensuremath{\nu}\ensuremath{\nu})H$. The performed data samples corresponding integrated luminosities of up 5.1 inverse femtobarns at $\sqrt{s}=7\text{ }\text{...
A bstract Properties of the Higgs boson are measured in H → ZZ 4ℓ (ℓ = e, μ ) decay channel. data sample proton-proton collisions at $$ \sqrt{s}=13 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msqrt><mml:mi>s</mml:mi></mml:msqrt><mml:mo>=</mml:mo><mml:mn>13</mml:mn></mml:math> TeV, collected with CMS detector LHC and corresponding to an integrated luminosity 35.9 fb −1 is used. The signal strength modifier , defined as ratio observed rate channel standard model expectation,...
The second-order azimuthal anisotropy Fourier harmonics, v2, are obtained in p−Pb and PbPb collisions over a wide pseudorapidity (η) range based on correlations among six or more charged particles. p-Pb data, corresponding to an integrated luminosity of 35 nb−1, were collected during the 2013 LHC run at nucleon-nucleon center-of-mass energy 5.02 TeV by CMS experiment. A sample semiperipheral collision data √sNN=2.76 TeV, 2.5 μb−1 covering similar particle multiplicities as is also analyzed...
The normalized differential cross section for top quark pair (tt-bar) production is measured in pp collisions at a centre-of-mass energy of 8 TeV the CERN LHC using CMS detector data corresponding to an integrated luminosity 19.7 inverse femtobarns. measurements are performed lepton + jets (e/mu jets) and dilepton (e+e-, mu+mu-, e+-mu-+) decay channels. tt-bar as function kinematic properties charged leptons, associated b quarks, system. compared with several predictions from perturbative...
At the start of Run 2 in 2015, LHC delivered proton-proton collisions at a center-of-mass energy 13 TeV. During (years 2015-2018) eventually reached luminosity 2.1 $\times$ 10$^{34}$ cm$^{-2}$ s$^{-1}$, almost three times that during 1 (2009-2013) and factor two larger than design value, leading to events with up mean about 50 simultaneous inelastic per bunch crossing (pileup). The CMS Level-1 trigger was upgraded prior 2016 improve selection physics challenging conditions posed by second...
A measurement of the coupling strength Higgs boson to a pair tau leptons is performed using events recorded in proton-proton collisions by CMS experiment at LHC 2016 center-of-mass energy 13 TeV. The data set corresponds an integrated luminosity 35.9 inverse femtobarns. H signal established with significance 4.9 standard deviations, be compared expected 4.7 deviations. best fit product observed production cross section and branching fraction 1.09 +0.27-0.26 times model expectation....