Efstathios Stiliaris

Prof. Dr. Efstathios Stiliaris

National and Kapodistrian University of Athens, Athens, Attikí, Greece
orcid

Research Focus & Metrics

Academic Career Length

40Years (1987-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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14 May 2015 in The European Physical Journal C
Verified
Journal Article
Open access
TCThe CMS Collaboration
The CMS Collaboration
VKV. Khachatryan
V. Khachatryan
ASA. M. Sirunyan
A. M. Sirunyan
ATA. Tumasyan
A. Tumasyan
WAW. Adam
W. Adam
VRV. Roinishvili
V. Roinishvili
Properties of the Higgs boson with mass near 125\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\,\text {GeV}$$\end{document}GeV are measured in proton-proton collisions with the CMS experiment at the LHC. Comprehensive sets of production and decay measurements are combined. The decay channels include \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\gamma \gamma $$\end{document}γγ, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathrm{Z}\mathrm{Z}$$\end{document}ZZ, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathrm{W}\mathrm{W}$$\end{document}WW, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\tau \tau $$\end{document}ττ, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathrm{b} \mathrm{b} $$\end{document}bb, and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mu \mu $$\end{document}μμ pairs. The data samples were collected in 2011 and 2012 and correspond to integrated luminosities of up to 5.1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\,\text {fb}^\text {-1}$$\end{document}fb-1 at 7\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\,\text {TeV}$$\end{document}TeV and up to 19.7\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\,\text {fb}^\text {-1}$$\end{document}fb-1 at 8\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\,\text {TeV}$$\end{document}TeV. From the high-resolution \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\gamma \gamma $$\end{document}γγ and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathrm{Z}\mathrm{Z}$$\end{document}ZZ channels, the mass of the Higgs boson is determined to be \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$125.02\,^{+0.26}_{-0.27} \,\text {(stat)} \,^{+0.14}_{-0.15} \,\text {(syst)} \,\text {GeV} $$\end{document}125.02-0.27+0.26(stat)-0.15+0.14(syst)GeV. For this mass value, the event yields obtained in the different analyses tagging specific decay channels and production mechanisms are consistent with those expected for the standard model Higgs boson. The combined best-fit signal relative to the standard model expectation is \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$1.00\,\pm 0.09\,\text {(stat)} \,^{+0.08}_{-0.07}\,\text {(theo)} \,\pm 0.07\,\text {(syst)} $$\end{document}1.00±0.09(stat)-0.07+0.08(theo)±0.07(syst) at the measured mass. The couplings of the Higgs boson are probed for deviations in magnitude from the standard model predictions in multiple ways, including searches for invisible and undetected decays. No significant deviations are found.

1 July 2013 in Physics Letters B
Verified
Journal Article
Open access
SCS. Chatrchyan
S. Chatrchyan
VKV. Khachatryan
V. Khachatryan
ASA.M. Sirunyan
A.M. Sirunyan
ATA. Tumasyan
A. Tumasyan
WAW. Adam
W. Adam
JSJ. Swanson
J. Swanson
Measurements of two- and four-particle angular correlations for charged particles emitted in pPb collisions are presented over a wide range in pseudorapidity and full azimuth. The data, corresponding to an integrated luminosity of approximately 31 nb−1, were collected during the 2013 LHC pPb run at a nucleon–nucleon center-of-mass energy of 5.02 TeV by the CMS experiment. The results are compared to 2.76 TeV semi-peripheral PbPb collision data, collected during the 2011 PbPb run, covering a similar range of particle multiplicities. The observed correlations are characterized by the near-side (|Δϕ|≈0) associated pair yields and the azimuthal anisotropy Fourier harmonics (vn). The second-order (v2) and third-order (v3) anisotropy harmonics are extracted using the two-particle azimuthal correlation technique. A four-particle correlation method is also applied to obtain the value of v2 and further explore the multi-particle nature of the correlations. Both associated pair yields and anisotropy harmonics are studied as a function of particle multiplicity and transverse momentum. The associated pair yields, the four-particle v2, and the v3 become apparent at about the same multiplicity. A remarkable similarity in the v3 signal as a function of multiplicity is observed between the pPb and PbPb systems. Predictions based on the color glass condensate and hydrodynamic models are compared to the experimental resultsThe Austrian Federal Ministry of Science and Research and the Austrian Science Fund ; the Belgian Fonds de la Recherche Scientifique, and Fonds voor Wetenschappelijk Onderzoek ; the Brazilian Funding Agencies ; the Bulgarian Ministry of Education and Science; CERN ; the Chinese Academy of Sciences, Ministry of Science and Technology, and National Natural Science Foundation of China ; the Colombian Funding Agency ; the Croatian Ministry of Science, Education and Sport ; the Research Promotion Foundation, Cyprus; the Ministry of Education and Research ; and European Regional Development Fund, Estonia; the Academy of Finland, Finnish Ministry of Education and Culture, and Helsinki Institute of Physics; the Institut National de Physique Nucleaire et de Physique des Particules/CNRS, and Commissariat a l’Energie Atomique et aux Energies Alternatives/CEA, France; the Bundesministerium fur Bildung und Forschung, Deutsche Forschungsgemeinschaft, and Helmholtz-Gemeinschaft Deutscher Forschungszentren, Germany; the General Secretariat for Research and Technology, Greece; the National Scientific Research Foundation, and National Office for Research and Technology, Hungary; the Department of Atomic Energy and the Department of Science and Technology, India; the Institute for Studies in Theoretical Physics and Mathematics, Iran; the Science Foundation, Ireland; the Istituto Nazionale di Fisica Nucleare, Italy; the Korean Ministry of Education, Science and Technology and the World Class University program of NRF, Republic of Korea; the Lithuanian Academy of Sciences; the Mexican Funding Agencies ; the Ministry of Business, Innovation and Employment, New Zealand; the Pakistan Atomic Energy Commission; the Ministry of Science and Higher Education and the National Science Centre, Poland; the Fundac¸ao para a Ciencia e a Tecnologia, Portugal; JINR, Dubna; the Ministry of Education and Science of the Russian Federation, the Federal Agency of Atomic Energy of the Russian Federation, Russian Academy of Sciences, and the Russian Foundation for Basic Research; the Ministry of Education, Science and Technological Development of Serbia; the Secretaria de Estado de Investigacio´n, Desarrollo e Innovacion and Programa Consolider-Ingenio 2010, Spain; the Swiss Funding Agencies ; the National Science Council, Taipei; the Thailand Center of Excellence in Physics, the Institute for the Promotion of Teaching Science and Technology of Thailand, Special Task Force for Activating Research and the National Science and Technology Development Agency of Thailand ; the Scientific and Technical Research Council of Turkey and Turkish Atomic Energy Authority ; the Science and Technology Facilities Council UK; the U.S. Department of Energy and the U.S. National Science Foundation ; European Union ; the Leventis Foundation ; the A. P. Sloan Foundation ; the Alexander von Humboldt Foundation ; the Belgian Federal Science Policy Office ; the Fonds pour la Formation a` la Recherche dans l’Industrie et dans l’Agriculture (FRIA-Belgium); the Agentschap voor Innovatie door Wetenschap en Technologie (IWTBelgium); the Ministry of Education Youth and Sports (MEYS) of Czech Republic; the Council of Science and Industrial Research India; the Compagnia di San Paolo (Torino); the HOMING PLUS program of Foundation for Polish Science cofinanced by EU Regional Development Fund; and the Thalis and Aristeia programs cofinanced by EU-ESF and the Greek NSRF.

29 March 2012 in The European Physical Journal C
Verified
Journal Article
Open access
PDF file
TCThe CMS Collaboration
The CMS Collaboration
SCS. Chatrchyan
S. Chatrchyan
VKV. Khachatryan
V. Khachatryan
ASA. M. Sirunyan
A. M. Sirunyan
ATA. Tumasyan
A. Tumasyan
JSJ. Swanson
J. Swanson
The transverse momentum spectra of charged particles have been measured in pp and PbPb collisions at [equation] by the CMS experiment at the LHC. In the transverse momentum range pT=5–10 GeV/ c, the...

1 March 2012 in Physics Letters B
Verified
Journal Article
Open access
SCS. Chatrchyan
S. Chatrchyan
VKV. Khachatryan
V. Khachatryan
ASA.M. Sirunyan
A.M. Sirunyan
ATA. Tumasyan
A. Tumasyan
WAW. Adam
W. Adam
JSJ. Swanson
J. Swanson

14 May 2014 in Physical Review D
Verified
Journal Article
Open access
PDF file
SCS. Chatrchyan
S. Chatrchyan
VKV. Khachatryan
V. Khachatryan
ASA. M. Sirunyan
A. M. Sirunyan
ATA. Tumasyan
A. Tumasyan
WAW. Adam
W. Adam
(C(CMS Collaboration)
(CMS Collaboration)
The properties of a Higgs boson candidate are measured in the H→ZZ→4ℓ decay channel, with ℓ=e, μ, using data from pp collisions corresponding to an integrated luminosity of 5.1  fb−1 at the center-of-mass energy of s=7  TeV and 19.7  fb−1 at s=8  TeV, recorded with the CMS detector at the LHC. The new boson is observed as a narrow resonance with a local significance of 6.8 standard deviations, a measured mass of 125.6±0.4(stat)±0.2(syst)  GeV, and a total width ≤3.4  GeV at the 95% confidence level. The production cross section of the new boson times its branching fraction to four leptons is measured to be 0.93−0.23+0.26(stat)−0.09+0.13(syst) times that predicted by the standard model. Its spin-parity properties are found to be consistent with the expectations for the standard-model Higgs boson. The hypotheses of a pseudoscalar and all tested spin-1 boson hypotheses are excluded at the 99% confidence level or higher. All tested spin-2 boson hypotheses are excluded at the 95% confidence level or higher.

27 October 2011 in Journal of High Energy Physics
Verified
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TCThe CMS collaboration
The CMS collaboration
SCS. Chatrchyan
S. Chatrchyan
VKV. Khachatryan
V. Khachatryan
ASA. M. Sirunyan
A. M. Sirunyan
ATA. Tumasyan
A. Tumasyan
MWM. Weinberg
M. Weinberg
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 pb−1. The measured inclusive cross sections are σ(pp → WX) × \( \mathcal{B}\left( {{\text{W}} \to \ell \nu } \right) \) = 10.31 ± 0.02 (stat.) ± 0.09 (syst.) ± 0.10 (th.) ± 0.41 (lumi.) nb and σ(pp → ZX) × \( \mathcal{B}\left( {{\text{Z}} \to {\ell^{+} }{\ell^{-} }} \right) \) = 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 (σ(pp → WX) × \( \mathcal{B}\left( {{\text{W}} \to \ell \nu } \right) \)/(σ(pp → ZX) × \( \mathcal{B}\left( {{\text{Z}} \to {\ell^{+} }{\ell^{-} }} \right) \) = 10.54 ± 0.07 (stat.) ± 0.08 (syst.) ± 0.16 (th.) and (σ(pp → W+ X) × \( \mathcal{B}\left( {{{\text{W}}^{ + }} \to {\ell^{+} }\nu } \right) \)/(σ(pp → W− X) × \( \mathcal{B}\left( {{{\text{W}}^{-} } \to {\ell^{-} }\bar{\nu }} \right) \) = 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.