Searching for light neutralinos with a displaced vertex at the LHC

We study a bino-like light neutralino (\(\tilde \chi_1^0\)) produced at the LHC from the decay of a scalar lepton (\(\tilde e_L\)) through the process \(pp\to \tilde e_{L} \to e\tilde \chi_1^0\) in the context of R-parity-violating (RPV) supersymmetry where \(\tilde \chi_1^0\) is the lightest supersymmetric particle. For small masses and RPV couplings, the neutralino is naturally long-lived and its decay products can be identified as displaced tracks. Following existing searches, we propose a displaced-vertex search strategy for such a light neutralino with a single RPV coupling switched on, \(\lambda'_{111}\), in the mass range \(10\,\mbox{GeV} \lesssim m_{\tilde \chi_1^0}\lesssim 230\,\mbox{GeV}\). We perform Monte Carlo simulations and conclude that at the high-luminosity LHC, the proposed search can probe values of \(\lambda'_{111}\) down to two orders of magnitude smaller than current bounds and up to 40 times stronger than projected limits from monolepton searches.