Light neutralinos at LHC in cosmologically-inspired scenarios: new benchmarks in the search for supersymmetry

TL;DR

This paper investigates the detection of light neutralinos at the LHC within cosmologically motivated supersymmetric models, proposing new benchmarks and analyzing their collider signatures to aid experimental searches.

Contribution

It introduces new benchmark scenarios for light neutralinos with masses below 50 GeV, analyzing their collider signatures and cosmological properties for the first time.

Findings

Identification of key neutralino properties at LHC

Proposal of new benchmark scenarios for light neutralinos

Analysis of expected signals and event rates

Abstract

We study how the properties of the four neutralino states, chi_i (i = 1, 2, 3, 4), can be investigated at the Large Hadron Collider (LHC), in the case when the lightest one, chi_1, has a mass m_chi < 50 GeV and is stable. This situation arises naturally in supersymmetric models where gaugino masses are not unified at a Grand Unified (GUT) scale and R-parity is conserved. The main features of these neutralino states are established by analytical and numerical analyses, and two scenarios are singled out on the basis of the cosmological properties required for the relic neutralinos. Signals expected at LHC are discussed through the main chain processes started by a squark, produced in the initial proton-proton scattering. We motivate the selection of some convenient benchmarks, in the light of the spectroscopical properties (mass spectrum and transitions) of the four neutralino states. Branching ratios and the expected total number of events are derived in the various benchmarks, and their relevance for experimental determination of neutralino properties is finally discussed.