Search for a narrow, spin-2 resonance decaying to a pair of Z bosons in the q q-bar l+l- final state

TL;DR

This paper reports a search for a narrow spin-2 resonance decaying into Z boson pairs in proton-proton collisions, setting limits on graviton masses and couplings with no evidence of such a resonance.

Contribution

First search for a spin-2 resonance decaying to Z bosons in the specified final state using CMS data at 7 TeV, establishing exclusion limits on graviton models.

Findings

No evidence for the resonance was observed.

Excluded graviton masses below 610 to 945 GeV depending on the model.

Set upper limits on production cross sections and branching fractions.

Abstract

Results are presented from a search for a narrow, spin-2 resonance decaying into a pair of Z bosons, with one Z-boson decaying into leptons (e+e- or mu+mu-) and the other into jets. An example of such a resonance is the Kaluza--Klein graviton, G[KK], predicted in Randall--Sundrum models. The analysis is based on a 4.9 inverse femtobarn sample of proton-proton collisions at a center-of-mass energy of 7 TeV, collected with the CMS detector at the LHC. Kinematic and topological properties including decay angular distributions are used to discriminate between signal and background. No evidence for a resonance is observed, and upper limits on the production cross sections times branching fractions are set. In two models that predict Z-boson spin correlations in graviton decays, graviton masses are excluded lower than a value which varies between 610 and 945 GeV, depending on the model and the strength of the graviton couplings.