Search for narrow resonances in dilepton mass spectra in pp collisions at s=7TeV

Abstract

European Commission; Federal Ministry of Science, Research and Economy (Austria); Agency for Innovation by Science and Technology (Belgium); Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brasil); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Brasil); Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro; Fundação de Amparo à Pesquisa do Estado de São Paulo; Colciencias (Colombia); Ministry of Science, Education and Sports of the Republic of Croatia; Research Promotion Foundation (Cyprus); Centre National de la Recherche Scientifique (France); Bundesministerium für Bildung und Forschung (Deutschland); Deutsche Forschungsgemeinschaft; General Secretariat of Research and Technology (Greece); National Office for Research and Technology (Hungary); Institute for Research in Fundamental Sciences (Iran); Science Foundation Ireland; Istituto Nazionale di Fisica Nucleare (Italia); National Research Foundation of Korea; Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (México); Consejo Nacional de Ciencia y Tecnología (México); Secretaría de Educación Pública (México); Universidad Autónoma de San Luis Potosí; Pakistan Atomic Energy Commission; Fundação para a Ciência e a Tecnologia (Portugal); Joint Institute for Nuclear Research (Russia); Russian Foundation for Basic Research; Ministry of Education, Science and Technological Development (Serbia); Ministerio de Ciencia e Innovación (España); Centro Nacional de Física de Partículas, Astropartículas y Nuclear (España); Swiss National Science Foundation; The Scientific and Technological Research Council of Turkey; Turkish Atomic Energy Authority; Science and Technology Facilities Council (UK); Department of Energy (US); National Science Foundation (US)A search for narrow, high-mass resonances decaying to electron or muon pairs has been performed using pp collision data collected at √s=7 TeV by the CMS experiment in 2011. The data sample corresponds to an integrated luminosity of approximately 5 inverse femtobarns. The event yields observed in the signal regions are consistent with predictions of the standard model backgrounds, and upper limits on the cross section times branching fraction for a resonance decaying to dileptons are extracted from a shape analysis of the dilepton invariant mass distribution. The resulting mass limits at 95% confidence level are 2330 GeV for the Z' in the Sequential Standard Model, 2000 GeV for the superstring-inspired Z'ψ resonance, 890 (540) GeV for the Stueckelberg extension Z'St with the mass parameter epsilon=0.06 (0.04), and 2140 (1810) GeV for Kaluza--Klein gravitons with the coupling parameter k/MPl of 0.10 (0.05). These limits are the most stringent to date.33 páginas, 6 figuras, 1 tabla.-- Sphicas, P. et al.-- Open access: This article is published Open Access at sciencedirect.com. It is distributed under the terms of the Creative Commons Attribution License 3.0.Peer reviewed