Search for an L − L gauge boson using Z → 4μ events in proton-proton collisions at √ s = 13 TeV
Author(s)CMS Collaboration; Abercrombie, Daniel Robert; Allen, B.; Azzolini, Virginia; Barbieri, Richard Alexander; Baty, Austin Alan; Bauer, Gerry P; Bi, R.; Brandt, S.; Busza, Wit; Cali, Ivan Amos; D'Alfonso, Mariarosaria; Demiragli, Zeynep; Gomez-Ceballos, Guillelmo; Goncharov, Maxim; Harris, Philip Coleman; Hsu, D.; Hu, M.; Iiyama, Yutaro; Innocenti, Gian Michele; Klute, Markus; Kovalskyi, Dmytro; Lee, Y. -J.; Levin, A.; Luckey Jr, P David; Maier, Benedikt; Marini, Andrea Carlo; McGinn, Christopher Francis; Mironov, Camelia Maria; Narayanan, S.; Niu, Xinmei; Paus, Christoph M. E.; Roland, Christof; Roland, G.; Stephans, George S. F.; Sumorok, Konstanty C; Tatar, K.; Velicanu, Dragos Alexandru; Wang, J; Wang, T.W.; Wyslouch, Boleslaw; Shi, Zhaozhong; ... Show more Show less
MetadataShow full item record
© 2019 The Author(s) 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.
DepartmentMassachusetts Institute of Technology. Department of Physics
"Search for an L − L gauge boson using Z → 4μ events in proton-proton collisions at √ s = 13 TeV."
Final published version