Searching for light neutralinos with a displaced vertex at the LHC

TL;DR

This paper proposes a novel displaced-vertex search strategy at the LHC for detecting light neutralinos in RPV supersymmetry, demonstrating improved sensitivity over current and projected bounds through Monte Carlo simulations.

Contribution

It introduces a new search method for long-lived neutralinos via displaced vertices, focusing on RPV couplings and specific mass ranges, with detailed simulation results.

Findings

Proposed search can probe smaller RPV couplings than current bounds.

Method is effective for neutralino masses between 10 and 230 GeV.

Significantly enhances detection sensitivity at the high-luminosity LHC.

Abstract

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.