Author
M. Szleper
Other affiliations: CERN
Bio: M. Szleper is an academic researcher from Northwestern University. The author has contributed to research in topics: Branching fraction & Large Hadron Collider. The author has an hindex of 23, co-authored 38 publications receiving 3317 citations. Previous affiliations of M. Szleper include CERN.
Papers
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TL;DR: In this article, the transverse momentum balance in dijet and γ/Z+jets events is used to measure the jet energy response in the CMS detector, as well as the transversal momentum resolution.
Abstract: Measurements of the jet energy calibration and transverse momentum resolution in CMS are presented, performed with a data sample collected in proton-proton collisions at a centre-of-mass energy of 7TeV, corresponding to an integrated luminosity of 36pb−1. The transverse momentum balance in dijet and γ/Z+jets events is used to measure the jet energy response in the CMS detector, as well as the transverse momentum resolution. The results are presented for three different methods to reconstruct jets: a calorimeter-based approach, the ``Jet-Plus-Track'' approach, which improves the measurement of calorimeter jets by exploiting the associated tracks, and the ``Particle Flow'' approach, which attempts to reconstruct individually each particle in the event, prior to the jet clustering, based on information from all relevant subdetectors
750 citations
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Durham University1, University of Helsinki2, University of Wisconsin-Madison3, University of Rochester4, University of Catania5, Weizmann Institute of Science6, University of Warsaw7, University of Southampton8, CERN9, Lawrence Livermore National Laboratory10, Indian Institute of Science11, University of Montpellier12, University of Zurich13, Spanish National Research Council14, ETH Zurich15, Stanford University16, Northwestern University17, University of Pittsburgh18, Carleton University19, University of Hamburg20, Moscow State University21, University of Florida22, Paul Scherrer Institute23, University of Würzburg24, Imperial College London25, Florida State University26, University of Florence27, University of Bonn28, University at Buffalo29, RWTH Aachen University30, University of Sheffield31, University of California, Irvine32, Laboratoire d'Annecy-le-Vieux de physique des particules33, Brookhaven National Laboratory34, Argonne National Laboratory35, University of Bergen36, University of Mainz37, Centers for Medicare and Medicaid Services38, Lancaster University39, University of California, Santa Cruz40, University of Copenhagen41, University of Tokyo42, Austrian Academy of Sciences43, University of Manchester44, University College London45, University of Edinburgh46, University of California, Davis47, University of California, Berkeley48, University of Glasgow49, University of Barcelona50, Max Planck Society51, University of Chicago52, University of Turin53, Royal Holloway, University of London54, Kobe University55, University of Oslo56, Kyoto University57
TL;DR: In this paper, the authors discuss the possible interplay between the Large Hadron Collider (LHC) and the International e(+)e(-) Linear Collider (ILC) in testing the Standard Model and in discovering and determining the origin of new physics.
422 citations
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S. Chatrchyan1, Vardan Khachatryan1, Albert M. Sirunyan1, Armen Tumasyan1 +2230 more•Institutions (144)
TL;DR: The observed (expected) upper limit on the invisible branching fraction at 0.58 (0.44) is interpreted in terms of a Higgs-portal model of dark matter interactions.
Abstract: A search for invisible decays of Higgs bosons is performed using the vector boson fusion and associated ZH production modes. In the ZH mode, the Z boson is required to decay to a pair of charged leptons or a $b\bar{b}$ quark pair. The searches use the 8 TeV pp collision dataset collected by the CMS detector at the LHC, corresponding to an integrated luminosity of up to 19.7 inverse femtobarns. Certain channels include data from 7 TeV collisions corresponding to an integrated luminosity of 4.9 inverse femtobarns. The searches are sensitive to non-standard-model invisible decays of the recently observed Higgs boson, as well as additional Higgs bosons with similar production modes and large invisible branching fractions. In all channels, the observed data are consistent with the expected standard model backgrounds. Limits are set on the production cross section times invisible branching fraction, as a function of the Higgs boson mass, for the vector boson fusion and ZH production modes. By combining all channels, and assuming standard model Higgs boson cross sections and acceptances, the observed (expected) upper limit on the invisible branching fraction at $m_H$=125 GeV is found to be 0.58 (0.44) at 95% confidence level. We interpret this limit in terms of a Higgs-portal model of dark matter interactions.
246 citations
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TL;DR: In this paper, a sample of 1.69 × 10 7 fully reconstructed π 0 → γ e + e − decay candidates collected by the NA48/2 experiment at CERN in 2003-2004 is analyzed to search for the dark photon (A ′ ) production in the π − 0 → − γ A ′ decay followed by the prompt A − → e + − decay.
243 citations
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TL;DR: In this paper, a measurement of W and Z production cross sections in pp collisions at 7 TeV is presented, where electron and muon decay channels are analyzed in a data sample collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 36 inverse picobarns.
Abstract: A measurement of inclusive W and Z production cross sections in pp collisions at sqrt(s)=7 TeV is presented. The electron and muon decay channels are analyzed in a data sample collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 36 inverse picobarns. The measured inclusive cross sections are sigma(pp-> WX) B(W-> l nu) = 10.30 +/- 0.02 (stat.) +/- 0.10 (syst.) +/- 0.10 (th.) +/- 0.41 (lumi.) nb and sigma(pp -> ZX) B(Z-> l^+l^-) = 0.974 +/- 0.007 (stat.) +/- 0.007 (syst.) +/- 0.018 (th.) +/- 0.039 (lumi.) nb, limited to the dilepton invariant mass range 60 to 120 GeV. The luminosity-independent cross section ratios are [sigma(pp->WX) B(W-> l nu)]/[sigma(pp-> ZX) B(Z->l^+l^-)] = 10.54 +/- 0.07 (stat.) +/- 0.08 (syst.) +/- 0.16 (th.) and [sigma(pp->W^+X) B(W^+ -> l^+nu)] / [sigma(pp->W^- X) B(W^- -> l^- nu)] = 1.421 +/- 0.006 (stat.) +/- 0.014 (syst.) +/- 0.029 (th.). The measured values agree with next-to-next-to-leading order QCD cross section calculations based on recent parton distribution functions.
227 citations
Cited by
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TL;DR: In this paper, results from searches for the standard model Higgs boson in proton-proton collisions at 7 and 8 TeV in the CMS experiment at the LHC, using data samples corresponding to integrated luminosities of up to 5.8 standard deviations.
8,857 citations
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TL;DR: In this article, the first determination of parton distributions of the nucleon at NLO and NNLO based on a global data set which includes LHC data: NNPDF2.3 is presented, which includes, besides the deep inelastic, Drell-Yan, gauge boson production and jet data already used in previous global PDF determinations, all relevant LHC Data for which experimental systematic uncertainties are currently available: ATLAS and LHCb W and Z rapidity distributions from the 2010 run, CMS W electron asymmetry data from the 2011 run,
1,809 citations
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TL;DR: In this paper, the subject of quantum electrodynamics is presented in a new form, which may be dealt with in two ways: using redundant variables and using a direct physical interpretation.
Abstract: THE subject of quantum electrodynamics is extremely difficult, even for the case of a single electron. The usual method of solving the corresponding wave equation leads to divergent integrals. To avoid these, Prof. P. A. M. Dirac* uses the method of redundant variables. This does not abolish the difficulty, but presents it in a new form, which may be dealt with in two ways. The first of these needs only comparatively simple mathematics and is directly connected with an elegant general scheme, but unfortunately its wave functions apply only to a hypothetical world and so its physical interpretation is indirect. The second way has the advantage of a direct physical interpretation, but the mathematics is so complicated that it has not yet been solved even for what appears to be the simplest possible case. Both methods seem worth further study, failing the discovery of a third which would combine the advantages of both.
1,398 citations
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TL;DR: In this article, a combined ATLAS and CMS measurements of the Higgs boson production and decay rates, as well as constraints on its couplings to vector bosons and fermions, are presented.
Abstract: Combined ATLAS and CMS measurements of the Higgs boson production and decay rates, as well as constraints on its couplings to vector bosons and fermions, are presented. The combination is based on the analysis of five production processes, namely gluon fusion, vector boson fusion, and associated production with a $W$ or a $Z$ boson or a pair of top quarks, and of the six decay modes $H \to ZZ, WW$, $\gamma\gamma, \tau\tau, bb$, and $\mu\mu$. All results are reported assuming a value of 125.09 GeV for the Higgs boson mass, the result of the combined measurement by the ATLAS and CMS experiments. The analysis uses the CERN LHC proton--proton collision data recorded by the ATLAS and CMS experiments in 2011 and 2012, corresponding to integrated luminosities per experiment of approximately 5 fb$^{-1}$ at $\sqrt{s}=7$ TeV and 20 fb$^{-1}$ at $\sqrt{s} = 8$ TeV. The Higgs boson production and decay rates measured by the two experiments are combined within the context of three generic parameterisations: two based on cross sections and branching fractions, and one on ratios of coupling modifiers. Several interpretations of the measurements with more model-dependent parameterisations are also given. The combined signal yield relative to the Standard Model prediction is measured to be 1.09 $\pm$ 0.11. The combined measurements lead to observed significances for the vector boson fusion production process and for the $H \to \tau\tau$ decay of $5.4$ and $5.5$ standard deviations, respectively. The data are consistent with the Standard Model predictions for all parameterisations considered.
1,193 citations
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TL;DR: In this paper, the theoretical and phenomenological aspects of the Next-to-Minimal Supersymmetric Standard Model (NMSSM) were reviewed, including the Higgs sector including radiative corrections and the 2-loop β -functions for all parameters of the general NMSSM.
1,019 citations