Probing light neutralinos from pair-produced sleptons with displaced vertices at the high-luminosity LHC

We study light neutralinos χ~10 with masses ranging from 10 GeV to several hundred GeV within the framework of R-parity-violating (RPV) supersymmetry. These light neutralinos can be long-lived, decaying with a macroscopic displacement (order cm) inside the LHC main detectors. Complementing previous works on the subject, here we focus on their production through the electroweak pair production of left-chiral sleptons e~L, with the signal process pp → e~L+e~L− → e+χ~10e−χ~10. In contrast to the previous study with a singly produced slepton, where the RPV coupling λ111′ induces both the production and decay of the light neutralino, in our scenario the production proceeds through Drell-Yan-like processes that are essentially independent of RPV couplings. Correspondingly, we implement a displaced-vertex search strategy for which our numerical analysis shows that the high-luminosity LHC can probe λ111′ values up to three orders of magnitude smaller, and neutralino masses up to about four times larger than those accessible in the previously studied single-slepton production scenario.