J. Keaveney
A5100709425- 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
- Quantum optics and atomic interactions
- Atomic and Subatomic Physics Research
- Medical Imaging Techniques and Applications
- Astrophysics and Cosmic Phenomena
- Radiation Detection and Scintillator Technologies
- Distributed and Parallel Computing Systems
- Cold Atom Physics and Bose-Einstein Condensates
- Black Holes and Theoretical Physics
- Superconducting Materials and Applications
- Particle Accelerators and Free-Electron Lasers
- Mechanical and Optical Resonators
- CCD and CMOS Imaging Sensors
- Advanced Data Storage Technologies
- Quantum Information and Cryptography
- Gamma-ray bursts and supernovae
- Nuclear reactor physics and engineering
- Random lasers and scattering media
University of Cape Town
2020-2025
Government of Catalonia
2024
A. Alikhanyan National Laboratory
2024
Atlas Scientific (United States)
2024
SR Research (Canada)
2024
Federación Española de Enfermedades Raras
2024
Deutsches Elektronen-Synchrotron DESY
2016-2023
The University of Adelaide
2020-2023
University of California, Santa Cruz
2023
Rutherford Appleton Laboratory
2023
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...
The properties of a Higgs boson candidate are measured in the $H\ensuremath{\rightarrow}ZZ\ensuremath{\rightarrow}4\ensuremath{\ell}$ decay channel, with $\ensuremath{\ell}=e$, $\ensuremath{\mu}$, using data from $pp$ collisions corresponding to an integrated luminosity $5.1\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ at center-of-mass energy $\sqrt{s}=7\text{ }\mathrm{TeV}$ and $19.7\text{ }{\mathrm{fb}}^{\ensuremath{-}\text{1}}$ $\sqrt{s}=8\text{ }\mathrm{TeV}$, recorded CMS detector...
A joint measurement is presented of the branching fractions $B^0_s\to\mu^+\mu^-$ and $B^0\to\mu^+\mu^-$ in proton-proton collisions at LHC by CMS LHCb experiments. The data samples were collected 2011 a centre-of-mass energy 7 TeV, 2012 8 TeV. combined analysis produces first observation decay, with statistical significance exceeding six standard deviations, best its fraction so far. Furthermore, evidence for decay obtained three deviations. measurements are statistically compatible SM...
Measurements of two- and four-particle angular correlations for charged particles emitted in pPb collisions are presented over a wide range pseudorapidity full azimuth. The data, corresponding to an integrated luminosity approximately 31 inverse nanobarns, were collected during the 2013 LHC run at nucleon-nucleon center-of-mass energy 5.02 TeV by CMS experiment. results compared 2.76 semi-peripheral PbPb collision 2011 run, covering similar particle multiplicities. observed characterized...
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...
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...
The Vertex Locator (VELO) is a silicon microstrip detector that surrounds the proton-proton interaction region in LHCb experiment. performance of during first years its physics operation reviewed. system operated vacuum, uses bi-phase CO2 cooling system, and sensors are moved to 7 mm from LHC beam for data taking. stability these characteristic features described, details material budget given. calibration timing processing algorithms implemented FPGAs described. fully characterised. have...
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 bstract search for the standard model Higgs boson decaying to a W-boson pair at LHC is reported. The event sample corresponds an integrated luminosity of 4.9 fb −1 and 19.4 collected with CMS detector in pp collisions $ \sqrt{s} = 7 8 TeV, respectively. candidates are selected events two or three charged leptons. An excess above background observed, consistent expectation from mass around 125 GeV. probability observe equal larger than one seen, under background-only hypothesis,...
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...
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...
We present an experimental measurement of the cooperative Lamb shift and Lorentz using atomic nanolayer with tunable thickness density. The arises due to exchange virtual photons between identical atoms. interference forward backward propagating fields is confirmed by dependence which has a spatial frequency equal $2k$, i.e. twice that optical field. demonstration interactions in easily scalable system opens door new domain for non-linear optics.
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 description is provided of the performance CMS detector for photon reconstruction and identification in proton-proton collisions at a centre-of-mass energy 8 TeV CERN LHC. Details are given on photons from deposits electromagnetic calorimeter (ECAL) extraction estimates. The electron tracks that convert to electrons tracker also described, as optimization its accurate modelling simulation, analysis Higgs boson decay into two photons. In barrel section ECAL, an resolution about 1% achieved...
The first direct search for lepton-flavour-violating decays of the recently discovered Higgs boson (H) is described. performed in H to mu tau[e] and tau[h] channels, where are tau leptons reconstructed electronic hadronic decay respectively. data sample used this was collected pp collisions at a centre-of-mass energy sqrt(s) = 8 TeV with CMS experiment CERN LHC corresponds an integrated luminosity 19.7 inverse femtobarns. sensitivity order magnitude better than existing indirect limits. A...
Results of searches for heavy stable charged particles produced in pp collisions at sqrt(s) = 7 and 8 TeV are presented corresponding to an integrated luminosity 5.0 inverse femtobarns 18.8 femtobarns, respectively. Data collected with the CMS detector used study momentum, energy deposition, time-of-flight signal candidates. Leptons electric charge between e/3 8e, as well bound states that can undergo exchange material, studied. Analysis results various combinations signatures inner tracker...
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...