Searching for light neutralinos with a displaced vertex at the LHC

Abstract

Abstract We study a bino-like light neutralino ($$ {\overset{\sim }{\chi}}_1^0 $$ χ ~ 1 0 ) produced at the LHC from the decay of a scalar lepton ($$ \tilde{e}_L $$ e ~ L ) through the process pp →$$ \tilde{e}_L $$ e ~ L →$$ e{\overset{\sim }{\chi}}_1^0 $$ e χ ~ 1 0 in the context of R-parity-violating (RPV) supersymmetry where $$ {\overset{\sim }{\chi}}_1^0 $$ χ ~ 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, $$ {\lambda}_{111}^{\prime } $$ λ 111 ′ , in the mass range 10 GeV ≲ $$ {m}_{{\overset{\sim }{\chi}}_1^0} $$ m χ ~ 1 0 ≲ 230 GeV. We perform Monte Carlo simulations and conclude that at the high-luminosity LHC, the proposed search can probe values of $$ {\lambda}_{111}^{\prime } $$ λ 111 ′ down to two orders of magnitude smaller than current bounds and up to 40 times smaller than projected limits from monolepton searches.