Observation of the Z → ψl + l − Decay in pp Collisions at ffiffi s p = 13 TeV
Name
PhysRevLett.121.141801.pdf
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Author(s)
The CMS Collaboration
Abercrombie, Daniel Robert
Allen, Branden
Azzolini, Virginia
Baty, Austin Alan
Bauer, Gerry P
Bi, Ran
Brandt, Stephanie Akemi
Busza, Wit
Cali, Ivan Amos
Date Issued
October 2018
Journal
Physical Review Letters
Citation
Sirunyan, A. M., A. Tumasyan, W. Adam, F. Ambrogi, E. Asilar, T. Bergauer, J. Brandstetter, et al. “Observation of the
Z→ψℓ+ℓ−
Decay in
Pp
Collisions at
S=13 TeV.” Physical Review Letters 121, no. 14 (October 4, 2018). doi:10.1103/physrevlett.121.141801.
Version
Final published version
Abstract
© 2018 CERN, for the CMS Collaboration. This Letter presents the observation of the rare Z boson decay Z→ψ + -. Here, ψ represents contributions from direct J/ψ and ψ(2S)→J/ψX, + - is a pair of electrons or muons, and the J/ψ meson is detected via its decay to μ+μ-. 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 ψ(2S)→J/ψX contribution, the ratio of the branching fraction of the exclusive decay Z→J/ψ + - to the decay Z→μ+μ-μ+μ- within a fiducial phase space is measured to be B(Z→J/ψ + -)/B(Z→μ+μ-μ+μ-)=0.67±0.18(stat)±0.05(syst).
MIT Department
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Laboratory for Nuclear Science
Terms of Use
Creative Commons Attribution 4.0 International license
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1103/PhysRevLett.121.141801
