Speaker
Description
In R-parity conserving supersymmetric extensions of the standard model, the lightest neutralino $\tilde{\chi}_{1}^{0}$, which is also the lightest supersymmetric particle (LSP), plays the role of the canonical dark matter particle candidate. The traditional $\tilde{\chi}_{1}^{0}$ searches using Drell-Yan processes suffer in the compressed spectrum scenarios, where the LSP mass is only slightly less than the masses of other charginos and neutralinos. Therefore, new experimental techniques are needed in order to facilitate the detection of missing $\tilde{\chi}_{1}^{0}$ momentum in the event and the identification of the soft decay products characterizing these scenarios. In this talk, we present a summary of the search for chargino ($\tilde{\chi}_{1}^{\pm}$) - neutralino ($\tilde{\chi}_{2}^{0}$) production via pure electroweak vector boson fusion processes using data from $pp$ collisions at = 13 TeV collected in 2016 with the CMS experiment at the LHC. The final states considered consist of one or zero leptons, large missing transverse momentum, and two jets with a large separation in rapidity. The observed dijet invariant mass and lepton-neutrino transverse mass distributions are consistent with the standard model predictions. Upper limits on the cross section for chargino $\tilde{\chi}_{1}^{\pm}$ and neutralino $\tilde{\chi}_{2}^{0}$ production associated with two jets are set. In the compressed mass spectra scenario, where 1 (30) GeV, gaugino masses up to 112 (215) GeV for the mass-degenerate particles $\tilde{\chi}_{1}^{\pm}$ and $\tilde{\chi}_{2}^{0}$ are excluded at 95\% CL. This analysis obtains the most stringent limits to date on the production of chargino and neutralinos in the compressed mass spectrum scenarios with 1 $\leq \Delta m <$ 3 GeV and 25 $\leq \Delta m <$ 50 GeV, where $\Delta m \equiv m(\tilde{\chi}_{1}^{\pm}) - m(\tilde{\chi}_{1}^{0})$.
