Abstract

This paper reports searches for heavy resonances decaying into ZZ or ZW using data from proton-proton collisions at a centre-of-mass energy of sqrt{s}=13 TeV. The data, corresponding to an integrated luminosity of 36.1 fb−1, were recorded with the ATLAS detector in 2015 and 2016 at the Large Hadron Collider. The searches are performed in final states in which one Z boson decays into either a pair of light charged leptons (electrons and muons) or a pair of neutrinos, and the associated W boson or the other Z boson decays hadronically. No evidence of the production of heavy resonances is observed. Upper bounds on the production cross sections of heavy resonances times their decay branching ratios to ZZ or ZW are derived in the mass range 300-5000GeV within the context of Standard Model extensions with additional Higgs bosons, a heavy vector triplet or warped extra dimensions. Production through gluon-gluon fusion, Drell-Yan or vector-boson fusion are considered, depending on the assumed model.

Highlights

  • Background estimates Diboson Top quarksTotal Data3.8 (±) 0.6 8.4 (±) 1.2 60 (±) 91.1 (±) 0.4 33.9 (±) 2.7 321.8 (±) 0.6 123 (±) 766 (±) 7 1433 (±) 34 143414.2 (±) 1.6 11.0 (±) 2.1 10.0 (±) 0.9 7.5 (±) 0.81728 (±) 34 6060 (±) 60177 (±) 21 20.6 (±) 2.2 1926 (±) 32 285 (±) 31 69 (±) 6 6420 (±) 60Resolved b-tagged 1.02 (±) 0.12 0.62 (±) 0.08 1740 (±) 40 167 (±) 22 908 (±) 24 2810 (±) 40 2843 Untagged 3.31 (±) 0.34 2.5 (±) 0.5 82200 (±) 400 2280 (±) 250 1500 (±) 130 86030 (±) 280 85928

  • This paper reports searches for heavy resonances decaying√into ZZ or ZW using data from proton-proton collisions at a centre-of-mass energy of s = 13 TeV

  • Searches for heavy resonanc√es decaying into ZZ or ZW are performed using proton-proton collision data produced at s = 13 TeV and recorded by the ATLAS detector at the Large Hadron Collider (LHC) in 2015 and 2016

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Summary

ATLAS detector

The ATLAS detector [20] at the Large Hadron Collider (LHC) [21] covers nearly the entire solid angle around the collision point, and consists of an inner tracking detector surrounded by a thin superconducting solenoidal magnet producing a 2 T magnetic field, electromagnetic and hadronic calorimeters, and a muon spectrometer incorporating three large toroid-magnet assemblies. The muon spectrometer (MS) consists of precision tracking chambers covering the region |η| < 2.7, and separate trigger chambers covering |η| < 2.4. The lowest ET or pT requirement without trigger prescaling was 26 GeV for both the electrons and muons. The lowest threshold without prescaling is 100 GeV This trigger is fully efficient for events passing the selection described below. All events are required to contain a primary vertex with at least two associated tracks

Signal models and simulation
Event reconstruction
Data control regions and background estimation
Background estimates Diboson Top quarks
ATLAS Simulation
Background estimation
Systematic uncertainties
Statistical and fit procedures
Limits on the production of heavy resonances
Effects of systematic uncertainties
Conclusion
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