Search for a narrow spin-2 resonance decaying to Z bosons in the semileptonic final state

A search for new particles decaying to two $\mathrm{Z}$ bosons with subsequent decay to a final state containing two leptons and two quarks, $\mathrm{X}\rightarrow\mathrm{ZZ}\rightarrow\mathrm{q\bar{q}}\ell^-\ell^+$, is presented. Results are based on data corresponding to an integrated luminosity of 19.8~fb$^{-1}$ of proton-proton collisions at $\sqrt{s}=8\,\text{TeV}$ and collected with the CMS detector at the CERN LHC. Jet substructure techniques are exploited for separating the signal from the standard model background when the boost of the $\mathrm{Z}$ causes the two quarks to merge into a single jet reconstructed in the detector. Limits on a narrow-width bulk Randall-Sundrum graviton model are set. Bulk gravitons with coupling constant $\tilde{k}=0.5$ and mass smaller than $710~\,\text{TeV}$ are excluded at the 95\% C.L. .