Department of Physics & Astronomy

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    Evidence for WW production from double-parton interactions in proton-proton collisions at root s=13 TeV
    (Springer, 2020) CMS Collaboration; Buccilli, A.; Cooper, S.I.; Henderson, C.; Rumerio, P.; West, C.; Yerevan Physics Institute; Belarusian State University; University of Antwerp; Vrije Universiteit Brussel; Universite Libre de Bruxelles; Ghent University; Universite Catholique Louvain; Centro Brasileiro de Pesquisas Fisicas; Universidade do Estado do Rio de Janeiro; Universidade Estadual Paulista; Universidade Federal do ABC (UFABC); Bulgarian Academy of Sciences; University of Sofia; Beihang University; Chinese Academy of Sciences; Institute of High Energy Physics, CAS; Peking University; Tsinghua University; Universidad de los Andes (Colombia); Universidad de Antioquia; University of Split; Rudjer Boskovic Institute; University of Cyprus; Charles University Prague; Escuela Politecnica Nacional Ecuador; Egyptian Academy of Scientific Research & Technology (ASRT); Egyptian Knowledge Bank (EKB); Egyptian Network of High Energy Physics (ENHEP); National Institute of Chemical Physics & Biophysics (NICPB); University of Helsinki; Helsinki Institute of Physics; Lappeenranta University of Technology; CEA; UDICE-French Research Universities; Universite Paris Saclay; Centre National de la Recherche Scientifique (CNRS); CNRS - National Institute of Nuclear and Particle Physics (IN2P3); Institut Polytechnique de Paris; Universites de Strasbourg Etablissements Associes; Universite de Strasbourg; Universite Claude Bernard Lyon 1; Georgian Technical University; Ivane Javakhishvili Tbilisi State University; RWTH Aachen University; Helmholtz Association; Deutsches Elektronen-Synchrotron (DESY); University of Hamburg; Karlsruhe Institute of Technology; National Centre of Scientific Research "Demokritos"; National & Kapodistrian University of Athens; National Technical University of Athens; University of Ioannina; Eotvos Lorand University; Eotvos Lorand Research Network; Hungarian Academy of Sciences; Hungarian Wigner Research Centre for Physics; Hungarian Institute for Nuclear Research; University of Debrecen; Eszterhazy Karoly Catholic University; Indian Institute of Science (IISC) - Bangalore; Homi Bhabha National Institute; National Institute of Science Education & Research (NISER); Panjab University; University of Delhi; Saha Institute of Nuclear Physics; Indian Institute of Technology System (IIT System); Indian Institute of Technology (IIT) - Madras; Bhabha Atomic Research Center (BARC); Tata Institute of Fundamental Research (TIFR); Indian Institute of Science Education & Research (IISER) Pune; University College Dublin; Istituto Nazionale di Fisica Nucleare (INFN); Universita degli Studi di Bari Aldo Moro; Politecnico di Bari; University of Bologna; University of Catania; University of Florence; University of Genoa; University of Milano-Bicocca; University of Naples Federico II; University of Basilicata; Guglielmo Marconi University; University of Padua; University of Trento; University of Pavia; University of Perugia; University of Pisa; Scuola Normale Superiore di Pisa; Sapienza University Rome; University of Turin; University of Eastern Piedmont Amedeo Avogadro; University of Trieste; Kyungpook National University; Chonnam National University; Hanyang University; Korea University; Kyung Hee University; Sejong University; Seoul National University (SNU); University of Seoul; Sungkyunkwan University (SKKU); Riga Technical University; Vilnius University; Universiti Malaya; Universidad de Sonora; CINVESTAV - Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico Nacional; Instituto Politecnico Nacional - Mexico; Universidad Iberoamericana Ciudad de Mexico; Benemerita Universidad Autonoma de Puebla; Universidad Autonoma de San Luis Potosi; University of Montenegro; University of Auckland; University of Canterbury; National Centre for Physics - Pakistan; Quaid I Azam University; AGH University of Science & Technology; National Centre for Nuclear Research; University of Warsaw; Laboratorio de Instrumentacao e Fisica Experimental de Particulas; Joint Institute for Nuclear Research - Russia; National Research Centre - Kurchatov Institute; Petersburg Nuclear Physics Institute; Russian Academy of Sciences; Institute for Nuclear Research of the Russian Academy of Sciences; Alikhanov Institute for Theoretical & Experimental Physics; Moscow Institute of Physics & Technology; National Research Nuclear University MEPhI (Moscow Engineering Physics Institute); Russian Academy of Science Lebedev Physical Institute; Lomonosov Moscow State University; Novosibirsk State University; Institute of High Energy Physics - IHEP; Tomsk Polytechnic University; Tomsk State University; University of Belgrade; Centro de Investigaciones Energeticas, Medioambientales Tecnologicas; Autonomous University of Madrid; University of Oviedo; Consejo Superior de Investigaciones Cientificas (CSIC); Universidad de Cantabria; CSIC - Instituto de Fisica de Cantabria (IFCA); University of Colombo; University Ruhuna; European Organization for Nuclear Research (CERN); Swiss Federal Institutes of Technology Domain; Paul Scherrer Institute; ETH Zurich; University of Zurich; National Central University; National Taiwan University; Chulalongkorn University; Cukurova University; Middle East Technical University; Bogazici University; Istanbul Technical University; Istanbul University; National Academy of Sciences Ukraine; Institute for Scintillation Materials of the National Academy of Sciences of Ukraine; Kharkov Institute of Physics & Technology; University of Bristol; UK Research & Innovation (UKRI); Science & Technology Facilities Council (STFC); STFC Rutherford Appleton Laboratory; Imperial College London; Brunel University; Baylor University; Catholic University of America; University of Alabama Tuscaloosa; Boston University; Brown University; University of California System; University of California Davis; University of California Los Angeles; University of California Riverside; University of California San Diego; University of California Santa Barbara; California Institute of Technology; Carnegie Mellon University; University of Colorado System; University of Colorado Boulder; Cornell University; United States Department of Energy (DOE); University of Chicago; Fermi National Accelerator Laboratory; State University System of Florida; University of Florida; Florida International University; Florida State University; Florida Institute of Technology; University of Illinois System; University of Illinois Chicago; University of Illinois Chicago Hospital; University of Iowa; Johns Hopkins University; University of Kansas; Kansas State University; Lawrence Livermore National Laboratory; University System of Maryland; University of Maryland College Park; Massachusetts Institute of Technology (MIT); University of Minnesota System; University of Minnesota Twin Cities; University of Mississippi; University of Nebraska System; University of Nebraska Lincoln; State University of New York (SUNY) System; State University of New York (SUNY) Buffalo; Northeastern University; Northwestern University; University of Notre Dame; University System of Ohio; Ohio State University; Princeton University; University of Puerto Rico; University of Puerto Rico Mayaguez; Purdue University System; Purdue University; Purdue University West Lafayette Campus; Rice University; University of Rochester; Rutgers State University New Brunswick; University of Tennessee System; University of Tennessee Knoxville; Texas A&M University System; Texas A&M University College Station; Texas Tech University System; Texas Tech University; Vanderbilt University; University of Virginia; Wayne State University; University of Wisconsin System; University of Wisconsin Madison; Technische Universitat Wien; Universidade Estadual de Campinas; Universidade Federal do Rio Grande do Sul; Universidade Federal de Mato Grosso do Sul; Universidade Federal de Pelotas; University of Chinese Academy of Sciences, CAS; Suez University; British University in Egypt; Universite de Haute-Alsace (UHA); Erzincan Binali Yildirim University; Brandenburg University of Technology Cottbus; Indian Institute of Technology (IIT) - Bhubaneswar; Institute of Physics Bhubaneswar (IOPB); Shoolini University; Visva Bharati University; Isfahan University of Technology; Italian National Agency New Technical Energy & Sustainable Economics Development; Agensi Nuklear Malaysia; Warsaw University of Technology; Academy of Sciences of Uzbekistan; Peter the Great St. Petersburg Polytechnic University; Budker Institute of Nuclear Physics; University of Siena; Adiyaman University; Sirnak University; Beykent University; Istanbul Aydin University; Mersin University; Piri Reis University; Gaziosmanpasa University; Ozyegin University; Izmir Institute of Technology; Marmara University; Kafkas University; Istanbul Bilgi University; Hacettepe University; University of Southampton; Monash University; Karamanoglu Mehmetbey University; Bingol University; Sinop University; Mimar Sinan Guzel Sanatlar University; Qatar Foundation (QF); Texas A&M University Qatar; University of Hyderabad
    A search for \(\text{WW}\) production from double-parton scattering processes using same-charge electron-muon and dimuon events is reported, based on proton-proton collision data collected at a center-of-mass energy of \(13\phantom{\rule{0.166667em}{0ex}}\text{TeV}\). The analyzed data set corresponds to an integrated luminosity of \(77.4\phantom{\rule{0.166667em}{0ex}}{\text{fb}}^{-1}\), collected using the CMS detector at the LHC in 2016 and 2017. Multivariate classifiers are used to discriminate between the signal and the dominant background processes. A maximum likelihood fit is performed to extract the signal cross section. This leads to the first evidence for \(\text{WW}\) production via double-parton scattering, with a significance of 3.9 standard deviations. The measured inclusive cross section is \(1.41±0.28\phantom{\rule{0.166667em}{0ex}}\text{(stat)}±0.28\phantom{\rule{0.166667em}{0ex}}\text{(syst)}\phantom{\rule{0.166667em}{0ex}}\text{pb}\).
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    Study of dijet events with a large rapidity gap between the two leading jets in pp collisions at root s=7 TeV
    (Springer, 2018) CMS Collaboration; Buccilli, A.; Cooper, S.I.; Henderson, C.; Rumerio, P.; West, C.; Yerevan Physics Institute; Belarusian State University; National Center of Particles & High Energy Physics - Belarus; University of Antwerp; Vrije Universiteit Brussel; Universite Libre de Bruxelles; Ghent University; Universite Catholique Louvain; University of Mons; Centro Brasileiro de Pesquisas Fisicas; Universidade do Estado do Rio de Janeiro; Universidade Estadual Paulista; Universidade Federal do ABC (UFABC); Bulgarian Academy of Sciences; University of Sofia; Beihang University; Chinese Academy of Sciences; Institute of High Energy Physics, CAS; Peking University; Universidad de los Andes (Colombia); University of Split; University of Cyprus; Charles University Prague; Egyptian Academy of Scientific Research & Technology (ASRT); Egyptian Knowledge Bank (EKB); Egyptian Network of High Energy Physics (ENHEP); National Institute of Chemical Physics & Biophysics (NICPB); University of Helsinki; Helsinki Institute of Physics; Lappeenranta University of Technology; CEA; UDICE-French Research Universities; Universite Paris Saclay; Centre National de la Recherche Scientifique (CNRS); CNRS - National Institute of Nuclear and Particle Physics (IN2P3); Institut Polytechnique de Paris; Universites de Strasbourg Etablissements Associes; Universite de Strasbourg; Universite Claude Bernard Lyon 1; Georgian Technical University; Ivane Javakhishvili Tbilisi State University; RWTH Aachen University; Helmholtz Association; Deutsches Elektronen-Synchrotron (DESY); University of Hamburg; Karlsruhe Institute of Technology; National Centre of Scientific Research "Demokritos"; National & Kapodistrian University of Athens; University of Ioannina; Eotvos Lorand University; Eotvos Lorand Research Network; Hungarian Academy of Sciences; Hungarian Wigner Research Centre for Physics; Hungarian Institute for Nuclear Research; University of Debrecen; Indian Institute of Science (IISC) - Bangalore; National Institute of Science Education & Research (NISER); Panjab University; University of Delhi; Homi Bhabha National Institute; Saha Institute of Nuclear Physics; Indian Institute of Technology System (IIT System); Indian Institute of Technology (IIT) - Madras; Bhabha Atomic Research Center (BARC); Tata Institute of Fundamental Research (TIFR); Indian Institute of Science Education & Research (IISER) Pune; University College Dublin; Istituto Nazionale di Fisica Nucleare (INFN); Universita degli Studi di Bari Aldo Moro; Politecnico di Bari; University of Bologna; University of Catania; University of Genoa; University of Milano-Bicocca; University of Naples Federico II; University of Basilicata; Guglielmo Marconi University; University of Padua; University of Trento; University of Pavia; University of Perugia; University of Pisa; Scuola Normale Superiore di Pisa; Sapienza University Rome; University of Turin; University of Eastern Piedmont Amedeo Avogadro; University of Trieste; Kyungpook National University; Jeonbuk National University; Chonnam National University; Hanyang University; Korea University; Seoul National University (SNU); University of Seoul; Sungkyunkwan University (SKKU); Vilnius University; Universiti Malaya; CINVESTAV - Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico Nacional; Universidad Iberoamericana Ciudad de Mexico; Benemerita Universidad Autonoma de Puebla; Universidad Autonoma de San Luis Potosi; University of Auckland; University of Canterbury; National Centre for Physics - Pakistan; Quaid I Azam University; National Centre for Nuclear Research; University of Warsaw; Laboratorio de Instrumentacao e Fisica Experimental de Particulas; Joint Institute for Nuclear Research - Russia; National Research Centre - Kurchatov Institute; Petersburg Nuclear Physics Institute; Russian Academy of Sciences; Institute for Nuclear Research of the Russian Academy of Sciences; Alikhanov Institute for Theoretical & Experimental Physics; Moscow Institute of Physics & Technology; National Research Nuclear University MEPhI (Moscow Engineering Physics Institute); Russian Academy of Science Lebedev Physical Institute; Lomonosov Moscow State University; Novosibirsk State University; Institute of High Energy Physics - IHEP; University of Belgrade; Centro de Investigaciones Energeticas, Medioambientales Tecnologicas; Autonomous University of Madrid; University of Oviedo; Consejo Superior de Investigaciones Cientificas (CSIC); Universidad de Cantabria; CSIC - Instituto de Fisica de Cantabria (IFCA); European Organization for Nuclear Research (CERN); Swiss Federal Institutes of Technology Domain; Paul Scherrer Institute; University of Zurich; National Central University; National Taiwan University; Chulalongkorn University; Cukurova University; Middle East Technical University; Bogazici University; Istanbul Technical University; National Academy of Sciences Ukraine; Institute for Scintillation Materials of the National Academy of Sciences of Ukraine; Kharkov Institute of Physics & Technology; University of Bristol; UK Research & Innovation (UKRI); Science & Technology Facilities Council (STFC); STFC Rutherford Appleton Laboratory; Imperial College London; Brunel University; Baylor University; Catholic University of America; University of Alabama Tuscaloosa; Boston University; Brown University; University of California System; University of California Davis; University of California Los Angeles; University of California Riverside; University of California San Diego; University of California Santa Barbara; California Institute of Technology; Carnegie Mellon University; University of Colorado System; University of Colorado Boulder; Cornell University; Fairfield University; United States Department of Energy (DOE); University of Chicago; Fermi National Accelerator Laboratory; State University System of Florida; University of Florida; Florida International University; Florida State University; Florida Institute of Technology; University of Illinois System; University of Illinois Chicago; University of Illinois Chicago Hospital; University of Iowa; Johns Hopkins University; University of Kansas; Kansas State University; Lawrence Livermore National Laboratory; University System of Maryland; University of Maryland College Park; Massachusetts Institute of Technology (MIT); University of Minnesota System; University of Minnesota Twin Cities; University of Mississippi; University of Nebraska System; University of Nebraska Lincoln; State University of New York (SUNY) System; State University of New York (SUNY) Buffalo; Northeastern University; Northwestern University; University of Notre Dame; University System of Ohio; Ohio State University; Princeton University; University of Puerto Rico; University of Puerto Rico Mayaguez; Purdue University System; Purdue University; Purdue University West Lafayette Campus; Rice University; University of Rochester; Rockefeller University; Rutgers State University New Brunswick; University of Tennessee System; University of Tennessee Knoxville; Texas A&M University System; Texas A&M University College Station; Texas Tech University System; Texas Tech University; Vanderbilt University; University of Virginia; Wayne State University; University of Wisconsin System; University of Wisconsin Madison; Technische Universitat Wien; Universidade Estadual de Campinas; Universidade Federal de Pelotas; Universidad de Antioquia; British University in Egypt; Cairo University; Zewail City of Science & Technology; Universite de Haute-Alsace (UHA); Brandenburg University of Technology Cottbus; Indian Institute of Technology (IIT) - Bhubaneswar; Visva Bharati University; Indian Institute of Science Education & Research (IISER) - Bhopal; Institute of Physics Bhubaneswar (IOPB); University Ruhuna; Isfahan University of Technology; University of Yazd; Islamic Azad University; University of Siena; International Islamic University Malaysia; Agensi Nuklear Malaysia; Warsaw University of Technology; Peter the Great St. Petersburg Polytechnic University; Budker Institute of Nuclear Physics; Riga Technical University; University of Bern; Adiyaman University; Istanbul Aydin University; Mersin University; Cag University - Turkey; Piri Reis University; Gaziosmanpasa University; Ozyegin University; Izmir Institute of Technology; Marmara University; Kafkas University; Istanbul Bilgi University; Yildiz Technical University; Hacettepe University; University of Southampton; Instituto de Astrofisica de Canarias; Utah System of Higher Education; Utah Valley University; Argonne National Laboratory; Erzincan Binali Yildirim University; Mimar Sinan Guzel Sanatlar University; Qatar Foundation (QF); Texas A&M University Qatar
    Events with no charged particles produced between the two leading jets are studied in proton-proton collisions at \(\sqrt{s}=7\) \(\phantom{\rule{0.166667em}{0ex}}\text{TeV}\). The jets were required to have transverse momentum \({p}_{T}^{\text{jet}}>40\) \(\phantom{\rule{0.166667em}{0ex}}\text{GeV}\) and pseudorapidity \(1.5<|{\eta }^{\text{jet}}|<4.7\), and to have values of \({\eta }^{\text{jet}}\) with opposite signs. The data used for this study were collected with the CMS detector during low-luminosity running at the LHC, and correspond to an integrated luminosity of 8 \(\phantom{\rule{0.166667em}{0ex}}{\text{pb}}^{-1}\). Events with no charged particles with \({p}_{T}>0.2\) \(\phantom{\rule{0.166667em}{0ex}}\text{GeV}\) in the interval \(-1<\eta <1\) between the jets are observed in excess of calculations that assume no color-singlet exchange. The fraction of events with such a rapidity gap, amounting to 0.5–1% of the selected dijet sample, is measured as a function of the \({p}_{T}\) of the second-leading jet and of the rapidity separation between the jets. The data are compared to previous measurements at the Tevatron, and to perturbative quantum chromodynamics calculations based on the Balitsky–Fadin–Kuraev–Lipatov evolution equations, including different models of the non-perturbative gap survival probability.