Search for high-mass resonances decaying into a Z boson pair in the $\ell\ell\nu\nu$ final state in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

A search for high-mass resonances in events with large missing transverse momentum and a Z boson decaying into $e^{+}e^{−}$ or $\mu^{+}\mu^{−}$ is performed using 3.2 $fb^{−1}$ of 13 TeV proton-proton collision data acquired by the ATLAS experiment in the 2015 run of the Large Hadron Collider. The discriminant variable for this search is the transverse mass obtained by combining the momentum of the Z boson and the missing transverse momentum. No significant deviation is found in the distribution of the transverse mass with respect to the Standard Model prediction and upper limits are set on the production cross section times branching fraction for high mass narrow width Higgs bosons decaying into Z boson pairs. The results are also interpreted in the framework of a spin-2 Randall-Sundrum graviton.