Search for Compressed Supersymmetry in Electroweak Vector Boson Fusion Topologies with 0-, 1-, and 2- Low Energy Lepton Final States in Proton-Proton Collisions at \sqrt{s}=13 TeV

Abstract

Regardless of its remarkable success, the standard model (SM) of particle physics is unable to explain experimental observations like dark matter (DM), or conceptual problems, like the hierarchy problem. Supersymmetry (SUSY) has been proposed to solve the SM hierarchy problem, and could also explain the particle nature of DM. This has motivated experimental searches for SUSY DM production at colliders, creating a connection between particle physics and cosmology. A search for electroweak SUSY production in $pp$ collision events with two energetic jets, large momentum imbalance and one, two or zero low energy charged leptons is presented. Jets are largely separated in rapidity, consistent with the topology in electroweak vector boson fusion (VBF) processes. The data sample corresponds to an integrated luminosity of $\mathcal{L}_{\mathsf{int}}=$137 fb$^{-1}$ of $pp$ collisions at $\sqrt{s}=13$ TeV collected during the LHC Run II by the CMS detector. Results are interpreted using the R-parity conserving minimal supersymmetric extension of the SM (MSSM), focusing on scenarios where the mass difference between the lightest supersymmetric particle (LSP) and other electroweak SUSY particles is small. In this region, the LSP has the right properties to co-annihilate with other SUSY particles and produce the observed DM relic density. The experimental features of VBF processes provide an increased sensitivity to compressed SUSY, compared to traditional searches. The observed dijet invariant mass and lepton-neutrino transverse mass distributions are used to search for the presence of new physics. The analysis with Run II data provides sensitivity which exceeds that of other searches to date in these compressed SUSY scenarios.