Search for an L − L gauge boson using Z → 4μ events in proton-proton collisions at TeV
A search for a narrow Z$$'$$ gauge boson with a mass between 5 and 70 GeV resulting from an $$L_{\mu}-L_{\tau}$$ $U(1)$ local gauge symmetry is reported. 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$$\to$$Z$$'\mu\mu\to4\mu$$ 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. 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. 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 $$\mathcal{B}$$(Z $$\to$$ Z$$' \mu \mu$$) $$\mathcal{B}$$(Z$$' \to\mu \mu$$), 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 $$L_{\mu}-L_{\tau}$$ models at the LHC and result in a significant increase in the excluded model parameter space.
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP)
- Contributing Organization:
- The CMS Collaboration
- Grant/Contract Number:
- AC02-07CH11359
- OSTI ID:
- 1636538
- Alternate ID(s):
- OSTI ID: 1475056
- Report Number(s):
- FERMILAB-PUB-18-532-CMS; arXiv:1808.03684; CMS-EXO-18-008; CERN-EP-2018-208; S037026931930214X; PII: S037026931930214X
- Journal Information:
- Physics Letters B, Journal Name: Physics Letters B Vol. 792 Journal Issue: C; ISSN 0370-2693
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- Netherlands
- Language:
- English
Web of Science
Search for an $L_{\mu}-L_{\tau}$ gauge boson using Z$\to4\mu$ events in proton-proton collisions at $\sqrt{s} =$ 13 TeV
|
text | January 2019 |
Search for an $L_{\mu}-L_{\tau}$ gauge boson using Z$\to4\mu$ events in proton-proton collisions at $\sqrt{s} =$ 13 TeV
|
text | January 2018 |
Discovering true muonium at LHCb
|
journal | September 2019 |
Sub-GeV dark matter model
|
journal | October 2019 |
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