Search for an L − L gauge boson using Z → 4μ events in proton-proton collisions at √ s = 13 TeV
Name
1-s2.0-S037026931930214X-main.pdf
Description
Published version
Size
1.08 MB
Format
Unknown
Checksum (MD5)
fe7b2be2288ce665e22965b5adfcf96f
Author(s)
CMS Collaboration
Abercrombie, Daniel Robert
Allen, B.
Azzolini, Virginia
Barbieri, Richard Alexander
Baty, Austin Alan
Bauer, Gerry P
Bi, Ran
Brandt, Stephanie Akemi
Busza, Wit
Date Issued
March 2019
Journal
Physics Letters B
Publisher
Elsevier BV
Citation
CMS Collaboration (Sirunyan, A. M. et al.). "Search for an L − L gauge boson using Z → 4μ events in proton-proton collisions at √ s = 13 TeV." Physics Letters B 792 (May 2019): 345-368. © 2019 The Author(s)
Version
Final published version
Abstract
A search for a narrow Z ′ gauge boson with a mass between 5 and 70 GeV resulting from an L μ −L τ U(1) local gauge symmetry is reported. Theories that predict such a particle have been proposed as an explanation of various experimental discrepancies, including the lack of a dark matter signal in direct-detection experiments, tension in the measurement of the anomalous magnetic moment of the muon, and reports of possible lepton flavor universality violation in B meson decays. A data sample of proton-proton collisions at a center-of-mass energy of 13 TeV is used, corresponding to an integrated luminosity of 77.3 fb −1 recorded in 2016 and 2017 by the CMS detector at the LHC. Events containing four muons with an invariant mass near the standard model Z boson mass are analyzed, and the selection is further optimized to be sensitive to the events that may contain Z→Z ′ μμ→4μ decays. The event yields are consistent with the standard model predictions. Upper limits of 10 −8 –10 −7 at 95% confidence level are set on the product of branching fractions B(Z→Z ′ μμ)B(Z ′ →μμ), depending on the Z ′ mass, which excludes a Z ′ boson coupling strength to muons above 0.004–0.3. These are the first dedicated limits on L μ −L τ models at the LHC and result in a significant increase in the excluded model parameter space. The results of this search may also be used to constrain the coupling strength of any light Z ′ gauge boson to muons.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Terms of Use
Creative Commons Attribution 4.0 International license
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1016/J.PHYSLETB.2019.01.072
