Search for exclusive or semi-exclusive gamma gamma production and observation of exclusive and semi-exclusive e(+)e(-) production in pp collisions at root s=7 TeV
Contribuinte(s) |
Universidade Estadual Paulista (UNESP) |
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Data(s) |
18/03/2015
18/03/2015
01/11/2012
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Resumo |
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) A search for exclusive or semi-exclusive gamma gamma production, pp -> p(()*()) + gamma gamma + p(()*()) (where p* stands for a diffractively-dissociated proton), and the observation of exclusive and semi-exclusive e(+)e(-) production, pp -> p(()*()) + e(+)e(-) + p(()*()), in proton-proton collisions at root s = 7 TeV, are presented. The analysis is based on a data sample corresponding to an integrated luminosity of 36 pb(-1) recorded by the CMS experiment at the LHC at low instantaneous luminosities. Candidate gamma gamma or e(+)e(-) events are selected by requiring the presence of two photons or a positron and an electron, each with transverse energy E-T > 5.5 GeV and pseudorapidity vertical bar eta vertical bar < 2.5, and no other particles in the region vertical bar eta vertical bar < 5.2. No exclusive or semi-exclusive diphoton candidates are found in the data. An upper limit on the cross section for the reaction pp -> p(()*()) + gamma gamma + p(()*()), within the above kinematic selections, is set at 1.18 pb at 95% confidence level. Seventeen exclusive or semi-exclusive dielectron candidates are observed, with an estimated background of 0.85 +/- 0.28 (stat.) events, in agreement with the QED-based prediction of 16.3 +/- 1.3 (syst.) events. |
Formato |
35 |
Identificador |
http://dx.doi.org/10.1007/JHEP11(2012)080 Journal Of High Energy Physics. New York: Springer, n. 11, 35 p., 2012. 1029-8479 http://hdl.handle.net/11449/116240 10.1007/JHEP11(2012)080 WOS:000312198500015 WOS000312198500015.pdf |
Idioma(s) |
eng |
Publicador |
Springer |
Relação |
Journal Of High Energy Physics |
Direitos |
openAccess |
Palavras-Chave | #Hadron-Hadron Scattering |
Tipo |
info:eu-repo/semantics/article |