Search for supersymmetry in proton-proton collisions at $\sqrt{s} =$ 13 TeV in events with high-momentum Z bosons and missing transverse momentum

TL;DR

This paper reports a search for supersymmetric particles in proton-proton collisions at 13 TeV, focusing on events with boosted Z bosons and missing transverse momentum, setting new exclusion limits on gluino mass.

Contribution

First search for BSM production of boosted Z boson pairs with missing transverse momentum, using jet substructure techniques at the LHC.

Findings

No significant excess over standard model backgrounds.

Excluded gluino masses up to 1920 GeV at 95% CL.

Demonstrated the effectiveness of jet substructure in identifying boosted Z bosons.

Abstract

A search for new physics in events with two highly Lorentz-boosted Z bosons and large missing transverse momentum is presented. The analyzed proton-proton collision data, corresponding to an integrated luminosity of 137 fb$^{-1}$, were recorded at $\sqrt{s} =$ 13 TeV by the CMS experiment at the CERN LHC. The search utilizes the substructure of jets with large radius to identify quark pairs from Z boson decays. Backgrounds from standard model processes are suppressed by requirements on the jet mass and the missing transverse momentum. No significant excess in the event yield is observed beyond the number of background events expected from the standard model. For a simplified supersymmetric model in which the Z bosons arise from the decay of gluinos, an exclusion limit of 1920 GeV on the gluino mass is set at 95% confidence level. This is the first search for beyond-standard-model production of pairs of boosted Z bosons plus large missing transverse momentum.