A new approach for detecting compressed bino/wino at the LHC

TL;DR

This paper proposes a new method to detect compressed bino/wino scenarios at the LHC, focusing on small mass splittings and using specific decay channels, with detailed simulations showing the potential sensitivity of future experiments.

Contribution

It introduces a novel detection strategy for compressed bino/wino scenarios at the LHC, including detailed Monte Carlo simulations and analysis of experimental sensitivities.

Findings

LHC can probe wino masses up to 150 GeV for small mass splittings.

Sensitivity reaches 5σ for ΔM=5 GeV and 2σ for ΔM=15 GeV.

Dark matter detection experiments like XENON-1T may not fully cover the parameter space.

Abstract

In some supersymmetric models like split supersymmetry or models with non-universal gaugino mass, bino (LSP) and winos (NLSP) may have rather small mass splitting in order to provide the correct dark matter relic density through bino/wino co-annihilation. Such a scenario with the compressed bino/wino is difficult to explore at the LHC. In this work we propose to probe this scenario from $pp \to j \tilde{\chi}^0_2 \tilde{\chi}^\pm_1$ followed by $\tilde{\chi}^0_2 \to \gamma \tilde{\chi}^0_1$ and $\tilde{\chi}^\pm_1 \to W^{*}\tilde{\chi}^0_1\to \ell^\pm \nu \tilde{\chi}^0_1$ (this method is also applicable to the compressed bino/higgsino scenario). Through a detailed Monte Carlo simulation for both the signal and the backgrounds, we find that for a mass splitting $\Delta M \sim 5-15$ GeV between bino (LSP) and wino (NLSP), the 14 TeV LHC with luminosity of 500$fb^{-1}$ can probe the wino up to 150 GeV (the sensitivity can reach $5\sigma$ for $\Delta M = 5$ GeV and $2\sigma$ for $\Delta M = 15$ GeV). We also investigate the dark matter detection sensitivities for this scenario and find that the planned XENON-1T(2017) cannot fully cover the parameter space with wino below 150 GeV allowed by relic density and the LUX limits.