Abstract
Keywords CMS; Physics; Tau; Higgs; Observation; LHC A measurement of the H[right arrow][tau][tau] signal strength is performed using events recorded in proton--proton collisions by the CMS experiment at the LHC in 2016 at a center-of-mass energy of 13 TeV. The data set corresponds to an integrated luminosity of 35.9 fb.sup.-1. The H[right arrow][tau][tau] signal is established with a significance of 4.9 standard deviations, to be compared to an expected significance of 4.7 standard deviations. The best fit of the product of the observed H[right arrow][tau][tau] signal production cross section and branching fraction is 1.09.sub.-0.26.sup.+0.27 times the standard model expectation. The combination with the corresponding measurement performed with data collected by the CMS experiment at center-of-mass energies of 7 and 8 TeV leads to an observed significance of 5.9 standard deviations, equal to the expected significance. This is the first observation of Higgs boson decays to [tau] leptons by a single experiment. Author Affiliation: Yerevan Physics Institute, Yerevan, Armenia Institut fur Hochenergiephysik, Wien, Austria Institute for Nuclear Problems, Minsk, Belarus Universiteit Antwerpen, Antwerpen, Belgium Vrije Universiteit Brussel, Brussel, Belgium Universite Libre de Bruxelles, Bruxelles, Belgium Ghent University, Ghent, Belgium Universite Catholique de Louvain, Louvain-la-Neuve, Belgium Universite de Mons, Mons, Belgium Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro, Brazil Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil (a) Universidade Estadual Paulista, Sao Paulo, Brazil (b) Universidade Federal do ABC, Sao Paulo, Brazil Institute for Nuclear Research and Nuclear Energy of Bulgaria Academy of Sciences, Bulgaria University of Sofia, Sofia, Bulgaria Beihang University, Beijing, China Institute of High Energy Physics, Beijing, China State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing, China Universidad de Los Andes, Bogota, Colombia University of Split, Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, Split, Croatia University of Split, Faculty of Science, Split, Croatia Institute Rudjer Boskovic, Zagreb, Croatia University of Cyprus, Nicosia, Cyprus Charles University, Prague, Czech Republic Universidad San Francisco de Quito, Quito, Ecuador Academy of Scientific Research and Technology of the Arab Republic of Egypt, Egyptian Network of High Energy Physics, Cairo, Egypt National Institute of Chemical Physics and Biophysics, Tallinn, Estonia Department of Physics, University of Helsinki, Helsinki, Finland Helsinki Institute of Physics, Helsinki, Finland Lappeenranta University of Technology, Lappeenranta, Finland IRFU, CEA, Universite Paris-Saclay, Gif-sur-Yvette, France Laboratoire Leprince-Ringuet, Ecole polytechnique, CNRS/IN2P3, Universite Paris-Saclay, Palaiseau, France Universite de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France Centre de Calcul de l'Institut National de Physique Nucleaire et de Physique des Particules, CNRS/IN2P3, Villeurbanne, France Universite de Lyon, Universite Claude Bernard Lyon 1, CNRS-IN2P3, Institut de Physique Nucleaire de Lyon, Villeurbanne, France Georgian Technical University, Tbilisi, Georgia Tbilisi State University, Tbilisi, Georgia RWTH Aachen University, I. Physikalisches Institut, Aachen, Germany RWTH Aachen University, III. Physikalisches Institut A, Aachen, Germany RWTH Aachen University, III. Physikalisches Institut B, Aachen, Germany Deutsches Elektronen-Synchrotron, Hamburg, Germany University of Hamburg, Hamburg, Germany Institut fur Experimentelle Kernphysik, Karlsruhe, Germany Institute of Nuclear and Particle Physics (INPP), NCSR Demokritos, Aghia Paraskevi, Greece National and Kapodistrian University of Athens, Athens, Greece National Technical University of Athens, Athens, Greece University of Ioannina, Ioannina, Greece MTA-ELTE Lendulet CMS Particle and Nuclear Physics Group, Eotvos Lorand University, Budapest, Hungary Wigner Research Centre for Physics, Budapest, Hungary Institute of Nuclear Research ATOMKI, Debrecen, Hungary Institute of Physics, University of Debrecen, Debrecen, Hungary Indian Institute of Science (IISc), Bangalore, India National Institute of Science Education and Research, Bhubaneswar, India Panjab University, Chandigarh, India University of Delhi, Delhi, India Saha Institute of Nuclear Physics, HBNI, Kolkata, India Indian Institute of Technology Madras, Madras, India Bhabha Atomic Research Centre, Mumbai, India Tata Institute of Fundamental Research-A, Mumbai, India Tata Institute of Fundamental Research-B, Mumbai, India Indian Institute of Science Education and Research (IISER), Pune, India Institute for Research in Fundamental Sciences (IPM), Tehran, Iran University College Dublin, Dublin, Ireland (a) INFN Sezione di Bari, Bari, Italy (b) Universita di Bari, Bari, Italy (c) Politecnico di Bari, Bari, Italy (a) INFN Sezione di Bologna, Bologna, Italy (b) Universita di Bologna, Bologna, Italy (a) INFN Sezione di Catania, Catania, Italy (b) Universita di Catania, Catania, Italy (a) INFN Sezione di Firenze, Firenze, Italy (b) Universita di Firenze, Firenze, Italy INFN Laboratori Nazionali di Frascati, Frascati, Italy (a) INFN Sezione di Genova, Genova, Italy (b) Universita di Genova, Genova, Italy (a) INFN Sezione di Milano-Bicocca, Milano, Italy (b) Universita di Milano-Bicocca, Milano, Italy (a) INFN Sezione di Napoli, Napoli, Italy (b) Universita di Napoli 'Federico II', Napoli, Italy (c) Universita della Basilicata, Potenza, Italy (d) Universita G. Marconi, Roma, Italy (a) INFN Sezione di Padova, Padova, Italy (b) Universita di Padova, Padova, Italy (c) Universita di Trento, Trento, Italy (a) INFN Sezione di Pavia, Pavia, Italy (b) Universita di Pavia, Pavia, Italy (a) INFN Sezione di Perugia, Perugia, Italy (b) Universita di Perugia, Perugia, Italy (a) INFN Sezione di Pisa, Pisa, Italy (b) Universita di Pisa, Pisa, Italy (c) Scuola Normale Superiore di Pisa, Pisa, Italy (a) INFN Sezione di Roma, Rome, Italy (b) Sapienza Universita di Roma, Rome, Italy (a) INFN Sezione di Torino, Torino, Italy (b) Universita di Torino, Torino, Italy (c) Universita del Piemonte Orientale, Novara, Italy (a) INFN Sezione di Trieste, Trieste, Italy (b) Universita di Trieste, Trieste, Italy Kyungpook National University, Daegu, Republic of Korea Chonbuk National University, Jeonju, Republic of Korea Chonnam National University, Institute for Universe and Elementary Particles, Kwangju, Republic of Korea Hanyang University, Seoul, Republic of Korea Korea University, Seoul, Republic of Korea Seoul National University, Seoul, Republic of Korea University of Seoul, Seoul, Republic of Korea Sungkyunkwan University, Suwon, Republic of Korea Vilnius University, Vilnius, Lithuania National Centre for Particle Physics, Universiti Malaya, Kuala Lumpur, Malaysia Centro de Investigacion y de Estudios Avanzados del IPN, Mexico City, Mexico Universidad Iberoamericana, Mexico City, Mexico Benemerita Universidad Autonoma de Puebla, Puebla, Mexico Universidad Autonoma de San Luis Potosi, San Luis Potosi, Mexico University of Auckland, Auckland, New Zealand University of Canterbury, Christchurch, New Zealand National Centre for Physics, Quaid-I-Azam University, Islamabad, Pakistan National Centre for Nuclear Research, Swierk, Poland Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw, Poland Laboratorio de Instrumentacao e Fisica Experimental de Particulas, Lisboa, Portugal Joint Institute for Nuclear Research, Dubna, Russia Petersburg Nuclear Physics Institute, Gatchina (St. Petersburg), Russia Institute for Nuclear Research, Moscow, Russia Institute for Theoretical and Experimental Physics, Moscow, Russia Moscow Institute of Physics and Technology, Moscow, Russia National Research Nuclear University 'Moscow Engineering Physics Institute' (MEPhI), Moscow, Russia P.N. Lebedev Physical Institute, Moscow, Russia Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, Russia Novosibirsk State University (NSU), Novosibirsk, Russia State Research Center of Russian Federation, Institute for High Energy Physics, Protvino, Russia University of Belgrade, Faculty of Physics and Vinca Institute of Nuclear Sciences, Belgrade, Serbia Centro de Investigaciones Energeticas Medioambientales y Tecnologicas (CIEMAT), Madrid, Spain Universidad Autonoma de Madrid, Madrid, Spain Universidad de Oviedo, Oviedo, Spain Instituto de Fisica de Cantabria (IFCA), CSIC-Universidad de Cantabria, Santander, Spain CERN, European Organization for Nuclear Research, Geneva, Switzerland Paul Scherrer Institut, Villigen, Switzerland Institute for Particle Physics, ETH Zurich, Zurich, Switzerland Universitat Zurich, Zurich, Switzerland National Central University, Chung-Li, Taiwan National Taiwan University (NTU), Taipei, Taiwan Chulalongkorn University, Faculty of Science, Department of Physics, Bangkok, Thailand Cukurova University, Physics Department, Science and Art Faculty, Adana, Turkey Middle East Technical University, Physics Department, Ankara, Turkey Bogazici University, Istanbul, Turkey Istanbul Technical University, Istanbul, Turkey Institute for Scintillation Materials of National Academy of Science of Ukraine, Kharkov, Ukraine National Scientific Center, Kharkov Institute of Physics and Technology, Kharkov, Ukraine University of Bristol, Bristol, United Kingdom Rutherford Appleton Laboratory, Didcot, United Kingdom Imperial College, London, United Kingdom Brunel University, Uxbridge, United Kingdom Baylor University, Waco, USA Catholic University of America, Washington DC, USA The University of Alabama, Tuscaloosa, USA Boston University, Boston, USA Brown University, Providence, USA University of California, Davis, Davis, USA University of California, Los Angeles, USA University of California, Riverside, Riverside, USA University of