B Kim

Publications (190)718.16 Total impact

• Source

  Available from: Francisco Matorras

  Article: Study of the Mass and Spin-Parity of the Higgs Boson Candidate via Its Decays to Z Boson Pairs.

  S Chatrchyan, V Khachatryan, A M Sirunyan, A Tumasyan, W Adam, E Aguilo, T Bergauer, M Dragicevic, J Erö, C Fabjan, [......], R Loveless, A Mohapatra, M U Mozer, I Ojalvo, F Palmonari, G A Pierro, I Ross, A Savin, W H Smith, J Swanson
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  ABSTRACT: A study is presented of the mass and spin-parity of the new boson recently observed at the LHC at a mass near 125 GeV. An integrated luminosity of 17.3 fb^{-1}, collected by the CMS experiment in proton-proton collisions at center-of-mass energies of 7 and 8 TeV, is used. The measured mass in the ZZ channel, where both Z bosons decay to e or μ pairs, is 126.2±0.6(stat)±0.2(syst) GeV. The angular distributions of the lepton pairs in this channel are sensitive to the spin-parity of the boson. Under the assumption of spin 0, the present data are consistent with the pure scalar hypothesis, while disfavoring the pure pseudoscalar hypothesis.
  Physical Review Letters 02/2013; 110(8):081803. · 7.37 Impact Factor
• Article: Search for Pair Production of Third-Generation Leptoquarks and Top Squarks in pp Collisions at sqrt[s]=7 TeV.

  S Chatrchyan, V Khachatryan, A M Sirunyan, A Tumasyan, W Adam, E Aguilo, T Bergauer, M Dragicevic, J Erö, C Fabjan, [......], J Leonard, R Loveless, A Mohapatra, I Ojalvo, F Palmonari, G A Pierro, I Ross, A Savin, W H Smith, J Swanson
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  ABSTRACT: Results are presented from a search for the pair production of third-generation scalar and vector leptoquarks, as well as for top squarks in R-parity-violating supersymmetric models. In either scenario, the new, heavy particle decays into a τ lepton and a b quark. The search is based on a data sample of pp collisions at sqrt[s]=7 TeV, which is collected by the CMS detector at the LHC and corresponds to an integrated luminosity of 4.8 fb^{-1}. The number of observed events is found to be in agreement with the standard model prediction, and exclusion limits on mass parameters are obtained at the 95% confidence level. Vector leptoquarks with masses below 760 GeV are excluded and, if the branching fraction of the scalar leptoquark decay to a τ lepton and a b quark is assumed to be unity, third-generation scalar leptoquarks with masses below 525 GeV are ruled out. Top squarks with masses below 453 GeV are excluded for a typical benchmark scenario, and limits on the coupling between the top squark, τ lepton, and b quark, λ_{333}^{'} are obtained. These results are the most stringent for these scenarios to date.
  Physical Review Letters 02/2013; 110(8):081801. · 7.37 Impact Factor
• Source

  Available from: Gulsen Onengut

  Article: Measurement of the Υ(1S), Υ(2S), and Υ(3S) Polarizations in pp Collisions at sqrt[s]=7 TeV.

  S Chatrchyan, V Khachatryan, A M Sirunyan, A Tumasyan, W Adam, E Aguilo, T Bergauer, M Dragicevic, J Erö, C Fabjan, [......], C Lazaridis, R Loveless, A Mohapatra, I Ojalvo, F Palmonari, G A Pierro, I Ross, A Savin, W H Smith, J Swanson
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  ABSTRACT: The polarizations of the Υ(1S), Υ(2S), and Υ(3S) mesons are measured in proton-proton collisions at sqrt[s]=7 TeV, using a data sample of Υ(nS)→μ^{+}μ^{-} decays collected by the CMS experiment, corresponding to an integrated luminosity of 4.9 fb^{-1}. The dimuon decay angular distributions are analyzed in three different polarization frames. The polarization parameters λ_{ϑ}, λ_{φ}, and λ_{ϑφ}, as well as the frame-invariant quantity λ[over ˜], are presented as a function of the Υ(nS) transverse momentum between 10 and 50 GeV, in the rapidity ranges |y|<0.6 and 0.6<|y|<1.2. No evidence of large transverse or longitudinal polarizations is seen in the explored kinematic region.
  Physical Review Letters 02/2013; 110(8):081802. · 7.37 Impact Factor
• Article: Transverse Momentum Distribution and Nuclear Modification Factor of Charged Particles in p+Pb Collisions at sqrt[s_{NN}]=5.02 TeV.

  B Abelev, J Adam, D Adamová, A M Adare, M M Aggarwal, G Aglieri Rinella, M Agnello, A G Agocs, A Agostinelli, Z Ahammed, [......], D Zhou, X Zhu, J Zhu, H Zhu, A Zichichi, A Zimmermann, G Zinovjev, Y Zoccarato, M Zynovyev, M Zyzak
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  ABSTRACT: The transverse momentum (p_{T}) distribution of primary charged particles is measured in minimum bias (non-single-diffractive) p+Pb collisions at sqrt[s_{NN}]=5.02 TeV with the ALICE detector at the LHC. The p_{T} spectra measured near central rapidity in the range 0.5<p_{T}<20 GeV/c exhibit a weak pseudorapidity dependence. The nuclear modification factor R_{pPb} is consistent with unity for p_{T} above 2 GeV/c. This measurement indicates that the strong suppression of hadron production at high p_{T} observed in Pb+Pb collisions at the LHC is not due to an initial-state effect. The measurement is compared to theoretical calculations.
  Physical Review Letters 02/2013; 110(8):082302. · 7.37 Impact Factor
• Source

  Available from: Varlen Grabski

  Article: Pseudorapidity Density of Charged Particles in p+Pb Collisions at sqrt[s_{NN}]=5.02 TeV.

  B Abelev, J Adam, D Adamová, A M Adare, M M Aggarwal, G Aglieri Rinella, M Agnello, A G Agocs, A Agostinelli, Z Ahammed, [......], Y Zhou, J Zhu, H Zhu, X Zhu, A Zichichi, A Zimmermann, G Zinovjev, Y Zoccarato, M Zynovyev, M Zyzak
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  ABSTRACT: The charged-particle pseudorapidity density measured over four units of pseudorapidity in nonsingle-diffractive p+Pb collisions at a center-of-mass energy per nucleon pair sqrt[s_{NN}]=5.02 TeV is presented. The average value at midrapidity is measured to be 16.81±0.71 (syst), which corresponds to 2.14±0.17 (syst) per participating nucleon, calculated with the Glauber model. This is 16% lower than in nonsingle-diffractive pp collisions interpolated to the same collision energy and 84% higher than in d+Au collisions at sqrt[s_{NN}]=0.2 TeV. The measured pseudorapidity density in p+Pb collisions is compared to model predictions and provides new constraints on the description of particle production in high-energy nuclear collisions.
  Physical Review Letters 01/2013; 110(3):032301. · 7.37 Impact Factor
• Article: Fold-preserving Electronic Cleansing using a Reconstruction Model Integrating Material Fractions and Structural Responses.

  H Lee, B Kim, J Lee, S Kim, Y Shin, T Kim
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  ABSTRACT: In this paper, we propose an electronic cleansing method using a novel reconstruction model for removing tagged materials (TMs) in computed tomography (CT) images. To address the partial volume (PV) and pseudo-enhancement (PEH) effects concurrently, material fractions and structural responses are integrated into a single reconstruction model. In our approach, colonic components including air, TM, interface layer between air and TM, and interface layer between soft-tissue (ST) and TM (ILST/TM) are first segmented. For each voxel in ILST/TM, the material fractions of ST and TM are derived using a two-material transition model, and the structural response to identify the folds submerged in the TM is calculated by the rut-enhancement function based on the eigenvalue signatures of the Hessian matrix. Then, the CT density value of each voxel in ILST/TM is reconstructed based on both the material fractions and structural responses. The material fractions remove the aliasing artifacts caused by PV effect in ILST/TM effectively while the structural responses avoid the erroneous cleansing of the submerged folds caused by PEH effect. Experimental results using 10 clinical datasets demonstrated that the proposed method showed higher cleansing quality and better preservation of submerged folds than the previous method, which was validated by the higher mean density values and fold preservation rates for manually segmented fold regions.
  IEEE transactions on bio-medical engineering 01/2013; · 2.15 Impact Factor
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  Available from: A. Ruiz

  Article: Evidence for Associated Production of a Single Top Quark and W Boson in pp Collisions at sqrt[s]=7 TeV.

  S Chatrchyan, V Khachatryan, A M Sirunyan, A Tumasyan, W Adam, E Aguilo, T Bergauer, M Dragicevic, J Erö, C Fabjan, [......], J Leonard, R Loveless, A Mohapatra, I Ojalvo, F Palmonari, G A Pierro, I Ross, A Savin, W H Smith, J Swanson
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  ABSTRACT: Evidence is presented for the associated production of a single top quark and W boson in pp collisions at sqrt[s]=7 TeV with the CMS experiment at the LHC. The analyzed data correspond to an integrated luminosity of 4.9 fb^{-1}. The measurement is performed using events with two leptons and a jet originated from a b quark. A multivariate analysis based on kinematic properties is utilized to separate the tt[over ¯] background from the signal. The observed signal has a significance of 4.0σ and corresponds to a cross section of 16_{-4}^{+5} pb, in agreement with the standard model expectation of 15.6±0.4_{-1.2}^{+1.0} pb.
  Physical Review Letters 01/2013; 110(2):022003. · 7.37 Impact Factor
• Article: Charge separation relative to the reaction plane in Pb-Pb collisions at sqrt[s_{NN}]=2.76 TeV.

  B Abelev, J Adam, D Adamová, A M Adare, M M Aggarwal, G Aglieri Rinella, A G Agocs, A Agostinelli, S Aguilar Salazar, Z Ahammed, [......], D Zhou, F Zhou, J Zhu, X Zhu, A Zichichi, A Zimmermann, G Zinovjev, Y Zoccarato, M Zynovyev, M Zyzak
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  ABSTRACT: Measurements of charge-dependent azimuthal correlations with the ALICE detector at the LHC are reported for Pb-Pb collisions at sqrt[s_{NN}]=2.76 TeV. Two- and three-particle charge-dependent azimuthal correlations in the pseudorapidity range |η|<0.8 are presented as a function of the collision centrality, particle separation in pseudorapidity, and transverse momentum. A clear signal compatible with a charge-dependent separation relative to the reaction plane is observed, which shows little or no collision energy dependence when compared to measurements at RHIC energies. This provides a new insight for understanding the nature of the charge-dependent azimuthal correlations observed at RHIC and LHC energies.
  Physical Review Letters 01/2013; 110(1):012301. · 7.37 Impact Factor
• Article: Search for Heavy Neutrinos and W_{R} Bosons with Right-Handed Couplings in a Left-Right Symmetric Model in pp Collisions at sqrt[s]=7 TeV.

  S Chatrchyan, V Khachatryan, A M Sirunyan, A Tumasyan, W Adam, E Aguilo, T Bergauer, M Dragicevic, J Erö, C Fabjan, [......], C Lazaridis, R Loveless, A Mohapatra, I Ojalvo, F Palmonari, G A Pierro, I Ross, A Savin, W H Smith, J Swanson
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  ABSTRACT: Results are presented from a search for heavy, right-handed muon neutrinos, N_{μ}, and right-handed W_{R} bosons, which arise in the left-right symmetric extensions of the standard model. The analysis is based on a 5.0 fb^{-1} sample of proton-proton collisions at a center-of-mass energy of 7 TeV, collected by the CMS detector at the Large Hadron Collider. No evidence is observed for an excess of events over the standard model expectation. For models with exact left-right symmetry, heavy right-handed neutrinos are excluded at 95% confidence level for a range of neutrino masses below the W_{R} mass, dependent on the value of M_{W_{R}}. The excluded region in the two-dimensional (M_{W_{R}}, M_{N_{μ}}) mass plane extends to M_{W_{R}}=2.5 TeV.
  Physical Review Letters 12/2012; 109(26):261802. · 7.37 Impact Factor
• Source

  Available from: Christos Leonidopoulos

  Article: Study of the Dijet Mass Spectrum in pp→W+jets Events at sqrt[s]=7 TeV.

  S Chatrchyan, V Khachatryan, A M Sirunyan, A Tumasyan, W Adam, E Aguilo, T Bergauer, M Dragicevic, J Erö, C Fabjan, [......], J Leonard, R Loveless, A Mohapatra, I Ojalvo, F Palmonari, G A Pierro, I Ross, A Savin, W H Smith, J Swanson
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  ABSTRACT: We report an investigation of the invariant mass spectrum of the two jets with highest transverse momentum in pp→W+2-jet and W+3-jet events to look for resonant enhancement. The data sample corresponds to an integrated luminosity of 5.0 fb^{-1} collected with the CMS detector at sqrt[s]=7 TeV. We find no evidence for the anomalous structure reported by the CDF Collaboration, and establish an upper limit of 5.0 pb at 95% confidence level on the production cross section for a generic Gaussian signal with mass near 150 GeV. Additionally, we exclude two theoretical models that predict a CDF-like dijet resonance near 150 GeV.
  Physical Review Letters 12/2012; 109(25):251801. · 7.37 Impact Factor
• Article: Measurement of the Cross Section for Electromagnetic Dissociation with Neutron Emission in Pb-Pb Collisions at sqrt[s_{NN}]=2.76 TeV.

  B Abelev, J Adam, D Adamová, A M Adare, M M Aggarwal, G Aglieri Rinella, A G Agocs, A Agostinelli, S Aguilar Salazar, Z Ahammed, [......], D Zhou, F Zhou, Y Zhou, J Zhu, X Zhu, A Zichichi, A Zimmermann, G Zinovjev, Y Zoccarato, M Zynovyev
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  ABSTRACT: The first measurement of neutron emission in electromagnetic dissociation of ^{208}Pb nuclei at the LHC is presented. The measurement is performed using the neutron zero degree calorimeters of the ALICE experiment, which detect neutral particles close to beam rapidity. The measured cross sections of single and mutual electromagnetic dissociation of Pb nuclei at sqrt[s_{NN}]=2.76 TeV with neutron emission are σ_{singleEMD}=187.4±0.2(stat)_{-11.2}^{+13.2}(syst) b and σ_{mutualEMD}=5.7±0.1(stat)±0.4(syst) b, respectively. The experimental results are compared to the predictions from a relativistic electromagnetic dissociation model.
  Physical Review Letters 12/2012; 109(25):252302. · 7.37 Impact Factor
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  Available from: C. Oppedisano

  Article: Pion, Kaon, and Proton Production in Central Pb-Pb Collisions at sqrt[s_{NN}]=2.76 TeV.

  B Abelev, J Adam, D Adamová, A M Adare, M M Aggarwal, G Aglieri Rinella, A G Agocs, A Agostinelli, S Aguilar Salazar, Z Ahammed, [......], Y Zhou, F Zhou, J Zhu, X Zhu, A Zichichi, A Zimmermann, G Zinovjev, Y Zoccarato, M Zynovyev, M Zyzak
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  ABSTRACT: In this Letter we report the first results on π^{±}, K^{±}, p, and p[over ¯] production at midrapidity (|y|<0.5) in central Pb-Pb collisions at sqrt[s_{NN}]=2.76 TeV, measured by the ALICE experiment at the LHC. The p_{T} distributions and yields are compared to previous results at sqrt[s_{NN}]=200 GeV and expectations from hydrodynamic and thermal models. The spectral shapes indicate a strong increase of the radial flow velocity with sqrt[s_{NN}], which in hydrodynamic models is expected as a consequence of the increasing particle density. While the K/π ratio is in line with predictions from the thermal model, the p/π ratio is found to be lower by a factor of about 1.5. This deviation from thermal model expectations is still to be understood.
  Physical Review Letters 12/2012; 109(25):252301. · 7.37 Impact Factor
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  Available from: Christos Leonidopoulos

  Article: A New Boson with a Mass of 125 GeV Observed with the CMS Experiment at the Large Hadron Collider

  D. Abbaneo, G. Abbiendi, M. Abbrescia, S. Abdullin, A. Abdulsalam, B.S. Acharya, D. Acosta, J.G. Acosta, A. Adair, W. Adam, [......], M.H. Zoeller, O. Zorba, P. Zotto, W. Zou, G. Zumerle, M. Zupan, A. Zuranski, R. Zuyeuski, M. Zvada, P. Zych
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  ABSTRACT: The Higgs boson was postulated nearly five decades ago within the framework of the standard model of particle physics and has been the subject of numerous searches at accelerators around the world. Its discovery would verify the existence of a complex scalar field thought to give mass to three of the carriers of the electroweak force—the W+, W–, and Z0 bosons—as well as to the fundamental quarks and leptons. The CMS Collaboration has observed, with a statistical significance of five standard deviations, a new particle produced in proton-proton collisions at the Large Hadron Collider at CERN. The evidence is strongest in the diphoton and four-lepton (electrons and/or muons) final states, which provide the best mass resolution in the CMS detector. The probability of the observed signal being due to a random fluctuation of the background is about 1 in 3 × 106. The new particle is a boson with spin not equal to 1 and has a mass of about 1.25 giga–electron volts. Although its measured properties are, within the uncertainties of the present data, consistent with those expected of the Higgs boson, more data are needed to elucidate the precise nature of the new particle.
  Science 12/2012; 338(6114):1569-1575. · 31.20 Impact Factor
• Article: Observation of Sequential Υ Suppression in PbPb Collisions.

  S Chatrchyan, V Khachatryan, A M Sirunyan, A Tumasyan, W Adam, E Aguilo, T Bergauer, M Dragicevic, J Erö, C Fabjan, [......], J Leonard, R Loveless, A Mohapatra, I Ojalvo, F Palmonari, G A Pierro, I Ross, A Savin, W H Smith, J Swanson
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  ABSTRACT: The suppression of the individual Υ(nS) states in PbPb collisions with respect to their yields in pp data has been measured. The PbPb and pp data sets used in the analysis correspond to integrated luminosities of 150 μb^{-1} and 230 nb^{-1}, respectively, collected in 2011 by the CMS experiment at the LHC, at a center-of-mass energy per nucleon pair of 2.76 TeV. The Υ(nS) yields are measured from the dimuon invariant mass spectra. The suppression of the Υ(nS) yields in PbPb relative to the yields in pp, scaled by the number of nucleon-nucleon collisions, R_{AA}, is measured as a function of the collision centrality. Integrated over centrality, the R_{AA} values are 0.56±0.08(stat)±0.07(syst), 0.12±0.04(stat)±0.02(syst), and lower than 0.10 (at 95% confidence level), for the Υ(1S), Υ(2S), and Υ(3S) states, respectively. The results demonstrate the sequential suppression of the Υ(nS) states in PbPb collisions at LHC energies.
  Physical Review Letters 11/2012; 109(22):222301. · 7.37 Impact Factor
• Article: Outbreaks and Diagnosis of Foot-and-Mouth Disease Serotype O in the Republic of Korea, April-June 2010.

  J-H Park, K-N Lee, Y-J Ko, S-M Kim, H-S Lee, J-Y Park, J-Y Yeh, M-J Kim, Y-H Lee, H-J Sohn, J-S Moon, I-S Cho, B Kim
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  ABSTRACT: Thirteen outbreaks of foot-and-mouth disease (FMD) were reported in pigs and cattle in Korea between 8 April and 4 June 2010. The FMD virus (FMDV) isolates were of serotype O, indicating that they were related to the virus strains of the Southeast Asia topotype that are circulating in East Asian countries. Animals carrying the viruses were identified by reverse transcriptase-polymerase chain reaction (RT-PCR) during a 29-day period between 8 April and 6 May, 2010. Prior to this outbreak, these FMDVs had not been detected in Korea and may therefore have been introduced from neighbouring countries into Ganghwa Island and subsequently spread inland to other areas, including Gimpo, Chungju and Cheongyang. Tests conducted to lift restrictions on animal movements lead to detection of two additional FMD-positive farms. Through appropriate responses, including swift diagnoses and culling policies, Korea was able to quickly regain its recognition as being free of FMD, without vaccination, by the World Organization for Animal Health (OIE) on 27 September 2010.
  Transboundary and Emerging Diseases 11/2012; · 1.81 Impact Factor
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  Available from: Christos Leonidopoulos

  Article: Search for New Physics in the Multijet and Missing Transverse Momentum Final State in Proton-Proton Collisions at sqrt[s]=7  TeV.

  S Chatrchyan, V Khachatryan, A M Sirunyan, A Tumasyan, W Adam, T Bergauer, M Dragicevic, J Erö, C Fabjan, M Friedl, [......], J Leonard, R Loveless, A Mohapatra, I Ojalvo, F Palmonari, G A Pierro, I Ross, A Savin, W H Smith, J Swanson
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  ABSTRACT: A search for physics beyond the standard model is performed in events with at least three jets and large missing transverse momentum produced in proton-proton collisions at a center-of-mass energy of sqrt[s]=7  TeV. No significant excess of events above the expected backgrounds is observed in 4.98  fb^{-1} of data collected with the CMS detector at the Large Hadron Collider. The results are presented in the context of the constrained minimal supersymmetric extension of the standard model and more generically for simplified models. For the simplified models of gluino-gluino and squark-squark production, gluino masses below 1.0 TeV and squark masses below 0.76 TeV are excluded in case the lightest supersymmetric particle mass is below 200 GeV. These results significantly extend previous searches.
  Physical Review Letters 10/2012; 109(17):171803. · 7.37 Impact Factor
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  Available from: Luigi Benussi

  Article: Measurement of the Pseudorapidity and Centrality Dependence of the Transverse Energy Density in Pb-Pb Collisions at sqrt[s_{NN}]=2.76  TeV.

  S Chatrchyan, V Khachatryan, A M Sirunyan, A Tumasyan, W Adam, T Bergauer, M Dragicevic, J Erö, C Fabjan, M Friedl, [......], J Leonard, R Loveless, A Mohapatra, I Ojalvo, F Palmonari, G A Pierro, I Ross, A Savin, W H Smith, J Swanson
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  ABSTRACT: The transverse energy (E_{T}) in Pb-Pb collisions at 2.76 TeV nucleon-nucleon center-of-mass energy (sqrt[s_{NN}]) has been measured over a broad range of pseudorapidity (η) and collision centrality by using the CMS detector at the LHC. The transverse energy density per unit pseudorapidity (dE_{T}/dη) increases faster with collision energy than the charged particle multiplicity. This implies that the mean energy per particle is increasing with collision energy. At all pseudorapidities, the transverse energy per participating nucleon increases with the centrality of the collision. The ratio of transverse energy per unit pseudorapidity in peripheral to central collisions varies significantly as the pseudorapidity increases from η=0 to |η|=5.0. For the 5% most central collisions, the energy density per unit volume is estimated to be about 14  GeV/fm^{3} at a time of 1  fm/c after the collision. This is about 100 times larger than normal nuclear matter density and a factor of 2.6 times higher than the energy density reported at sqrt[s_{NN}]=200  GeV at the Relativistic Heavy Ion Collider.
  Physical Review Letters 10/2012; 109(15):152303. · 7.37 Impact Factor
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  Available from: Luigi Benussi

  Article: Search for a W^{'} or Techni-ρ Decaying into WZ in pp Collisions at sqrt[s]=7  TeV.

  S Chatrchyan, V Khachatryan, A M Sirunyan, A Tumasyan, W Adam, E Aguilo, T Bergauer, M Dragicevic, J Erö, C Fabjan, [......], J Leonard, R Loveless, A Mohapatra, I Ojalvo, F Palmonari, G A Pierro, I Ross, A Savin, W H Smith, J Swanson
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  ABSTRACT: A search is performed in pp collisions at sqrt[s]=7  TeV for exotic particles decaying via WZ to final states with electrons and muons. The data sample corresponds to an integrated luminosity of approximately 5  fb^{-1}. No significant excess is observed in the data above the expected standard model background. Upper bounds at 95% confidence level are set on the production cross section of the W^{'} boson described by the sequential standard model and on the W^{'} WZ coupling. W^{'} bosons with masses below 1143 GeV are excluded. Limits are also set in the context of low-scale technicolor models, under a range of assumptions concerning the model parameters.
  Physical Review Letters 10/2012; 109(14):141801. · 7.37 Impact Factor
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  Available from: Alexander Belyaev

  Article: Search for a Light Pseudoscalar Higgs Boson in the Dimuon Decay Channel in pp Collisions at sqrt[s]=7  TeV.

  S Chatrchyan, V Khachatryan, A M Sirunyan, A Tumasyan, W Adam, T Bergauer, M Dragicevic, J Erö, C Fabjan, M Friedl, [......], J Leonard, R Loveless, A Mohapatra, I Ojalvo, F Palmonari, G A Pierro, I Ross, A Savin, W H Smith, J Swanson
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  ABSTRACT: The dimuon invariant mass spectrum is searched in the range between 5.5 and 14 GeV for a light pseudoscalar Higgs boson a, predicted in a number of new physics models, including the next-to-minimal supersymmetric standard model. The data sample used in the search corresponds to an integrated luminosity of 1.3  fb^{-1} collected in pp collisions at sqrt[s]=7  TeV with the CMS detector at the LHC. No excess is observed above the background predictions and upper limits are set on the cross section times branching fraction σ×B(pp→a→μ^{+}μ^{-}) in the range of 1.5-7.5 pb. These results improve on existing bounds on the abb[over ¯] coupling for m_{a}<m_{Υ(1S)} and are the first significant limits for m_{a}>m_{Υ(3S)}. Constraints on the supersymmetric parameter space are presented in the context of the next-to-minimal model.
  Physical Review Letters 09/2012; 109(12):121801. · 7.37 Impact Factor
• Article: Persistent Brain Network Homology from the Perspective of Dendrogram.

  H Lee, H Kang, M Chung, B Kim, D Lee
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  ABSTRACT: The brain network is usually constructed by estimating the connectivity matrix and thresholding it at an arbitrary level. The problem with this standard method is that we do not have any generally accepted criteria for determining a proper threshold. Thus, we propose a novel multiscale framework that models all brain networks generated over every possible threshold. Our approach is based on persistent homology and its various representations such as the Rips filtration, barcodes and dendrograms. This new persistent homological framework enables us to quantify various persistent topological features at different scales in a coherent manner. The barcode is used to quantify and visualize the evolutionary changes of topological features such as the Betti numbers over different scales. By incorporating additional geometric information to the barcode, we obtain a single linkage dendrogram that shows the overall evolution of the network. The difference between the two networks is then measured by the Gromov-Hausdorff distance over the dendrograms. As an illustration, we modeled and differentiated the FDGPET based functional brain networks of 24 attention-deficit hyperactivity disorder children, 26 autism spectrum disorder children and 11 pediatric control subjects.
  IEEE transactions on medical imaging. 09/2012;