Search for supersymmetry with a compressed mass spectrum in the vector boson fusion topology with 1-lepton and 0-lepton final states in proton-proton collisions at $\sqrt{s}=$ 13 TeV

A search for supersymmetric particles produced in the vector boson fusion topology in proton-proton collisions is presented. The search targets final states with one or zero leptons, large missing transverse momentum, and two jets with a large separation in rapidity. The data sample corresponds to an integrated luminosity of 35.9 fb$^{−1}$ of proton-proton collisions at $\sqrt{s}$ = 13 TeV collected in 2016 with the CMS detector at the LHC. The observed dijet invariant mass and lepton-neutrino transverse mass spectra are found to be consistent with the standard model predictions. Upper limits are set on the cross sections for chargino $\left({\tilde{\upchi}}_1^{\pm}\right)$ and neutralino $\left({\tilde{\upchi}}_2^0\right)$ production with two associated jets. For a compressed mass spectrum scenario in which the ${\tilde{\upchi}}_1^{\pm }$ and ${\tilde{\upchi}}_2^0$ decays proceed via a light slepton and the mass difference between the lightest neutralino ${\tilde{\upchi}}_1^0$ and the mass-degenerate particles ${\tilde{\upchi}}_1^{\pm }$ and ${\tilde{\upchi}}_2^0$ is 1 (30) GeV, the most stringent lower limit to date of 112 (215) GeV is set on the mass of these latter two particles.