Abstract
The ATLAS experiment at the CERN Large Hadron Collider has performed searches for new, heavy bosons decaying to $WW$, $WZ$ and $ZZ$ final states in multiple decay channels using 20.3 fb$^{-1}$ of $pp$ collision data at $\sqrt{s} = 8$ TeV. In the current study, the results of these searches are combined to provide a more stringent test of models predicting heavy resonances with couplings to vector bosons. Direct searches for a charged diboson resonance decaying to WZ in the $\ell\nu\ell'\ell'$ ($\ell = \mu, e$) , $\ell\ell q \bar{q}$, $\ell \nu q \bar{q}$ and fully hadronic final states are combined and upper limits on the rate of production times branching ratio to the $WZ$ bosons are compared with predictions of an extended gauge model with a heavy $W'$ boson. In addition, direct searches for a neutral diboson resonance decaying to $WW$ and $ZZ$ in the $\ell \ell q \bar{q}$, $\ell \nu q \bar{q}$, and fully hadronic final states are combined and upper limits on the rate of production times branching ratio to the $WW$ and $ZZ$ bosons are compared with predictions for a heavy, spin-2 graviton in an extended Randall--Sundrum model where the Standard Model fields are allowed to propagate in the bulk of the extra dimension.
Highlights
The naturalness argument associated with the small mass of the recently discovered Higgs boson [1,2,3,4] suggests that the Standard Model (SM) is conceivably to be extended by a theory that includes additional particles and interactions at the TeV scale
The results presented in this article use the√dataset collected in 2012 by ATLAS from the LHC pp collisions at s = 8 TeV, using a single-lepton trigger [33] with a pT threshold of 24 GeV, or a single large-radius jet trigger with a pT threshold of 360 GeV
For the full combination the largest deviation from the background-only expectation is found in the extended gauge model (EGM) W search at around 2.0 TeV with a p0-value corresponding to 2.5 standard deviations (σ )
Summary
The naturalness argument associated with the small mass of the recently discovered Higgs boson [1,2,3,4] suggests that the Standard Model (SM) is conceivably to be extended by a theory that includes additional particles and interactions at the TeV scale. Many such extensions of the SM, such as extended gauge models [5,6,7], models of warped extra dimensions [8,9,10], technicolour [11,12,13,14], and more generic composite Higgs models [15,16], predict the existence of massive resonances decaying to pairs of W and Z bosons. The leptonically decaying W → ν must have pT( ν) > 400 GeV, where pT( ν) is reconstructed from the sum of the charged-lepton momentum vector and vector
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