Probing Bino-Wino Coannihilation at the LHC

TL;DR

This paper investigates bino-wino coannihilation in mini-split supersymmetry, highlighting the potential for detecting long-lived neutral winos via displaced vertices at the LHC, which could shed light on bino dark matter.

Contribution

It demonstrates that neutral winos can have macroscopic decay lengths, enabling displaced vertex detection, and assesses current and future LHC constraints on this scenario.

Findings

A sizable parameter space can be probed at 8 TeV LHC.

Displaced vertex searches can significantly extend detection reach.

The study supports the viability of bino dark matter in mini-split SUSY.

Abstract

We study bino-wino coannihilation scenario in the so-called spread or mini-split supersymmetry. We show that, in this model, a neutral wino has a macroscopic decay length in a wide range of parameter space. This characteristic feature could be observed as a displaced vertex plus missing transverse energy event at the LHC. In this paper, we study the current constraints and future prospects on the scenario based on the displaced vertex search performed by the ATLAS collaboration. It is found that a sizable parameter region can be probed at the 8 TeV LHC run. This search strategy will considerably extend its reach at the next stage of the LHC running, and thus play a crucial role to examine a possibility of bino dark matter in the mini-split type supersymmetric models.