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Title
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Observation of the Z -> decay in pp collisions at =13 TeV
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Author
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Institution/Organisation
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CMS Collaboration
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Abstract
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| This Letter presents the observation of the rare Z boson decay Z -> psi l(+)l(-). Here, psi represents contributions from direct J/psi and psi(2S) -> J/psi X, l(+)l(-) is a pair of electrons or muons, and the J/psi meson is detected via its decay to mu(+)mu(-). The sample of proton-proton collision data, collected by the CMS experiment at the LHC at a center-of-mass energy of 13 TeV, corresponds to an integrated luminosity of 35.9 fb(-1). The signal is observed with a significance in excess of 5 standard deviations. After subtraction of the psi(2S) -> J/psi X contribution, the ratio of the branching fraction of the exclusive decay Z -> J/psi X, l(+) l(-) to the decay Z -> mu(+)mu(-)mu(+)mu(-) within a fiducial phase space is measured to be B(Z -> J/psi X, l(+) l(-))/B(Z -> mu(+)mu(-)mu(+)mu(-)) = 0.67 +/- 0.18(stat) +/- 0.05(syst). |
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Language
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English
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Source (journal)
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Physical review letters. - New York, N.Y., 1958, currens
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Publication
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New York, N.Y.
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American Physical Society
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2018
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ISSN
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0031-9007
[print]
1079-7114
[online]
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Volume/pages
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121
:14
(2018)
, 17 p.
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Article Reference
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141801
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ISI
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000446406900001
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Pubmed ID
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30339440
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Medium
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E-only publicatie
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Full text (Publisher's DOI)
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Full text (open access)
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