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

TL;DR

This paper investigates the detection of long-lived light neutralinos produced via slepton pair production at the high-luminosity LHC, proposing a displaced-vertex search strategy that extends the sensitivity to smaller RPV couplings and higher neutralino masses.

Contribution

It introduces a novel approach focusing on slepton pair production and displaced vertices, expanding the parameter space accessible at the LHC compared to previous single-slepton studies.

Findings

High-luminosity LHC can probe neutralino masses up to four times larger.

Sensitivity to RPV coupling $ ext{λ'}_{111}$ improves by three orders of magnitude.

Displaced-vertex signatures effectively identify long-lived neutralinos.

Abstract

We study light neutralinos ($\tilde \chi_1^0$) 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 ($\tilde e_{L}$), with the signal process $pp\to \tilde e^+_{L} \tilde e^-_{L} \to e^+ \tilde \chi_1^0 e^- \tilde \chi_1^0$. In contrast to the previous study with a singly produced slepton, where the RPV coupling $\lambda'_{111}$ 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 $\lambda'_{111}$ values up to three orders of magnitude smaller, and neutralino masses up to about four times larger than those accesible in the previously studied single-slepton production scenario.