# The Not-So-Well Tempered Neutralino

## TL;DR

This paper investigates the parameter space of the MSSM where neutralinos are viable dark matter candidates, considering constraints from dark matter detection and collider searches, especially focusing on less-explored 'not-so-well-tempered' scenarios.

## Contribution

It provides a detailed analysis of MSSM neutralino models that evade current dark matter detection constraints, highlighting regions compatible with both cosmology and collider experiments.

## Key findings

- Certain bino-Higgsino and bino-wino models remain viable despite detection constraints.
- Partial dark matter composition relaxes detection bounds, expanding the allowed parameter space.
- Complementarity between LHC searches and dark matter experiments is crucial for probing these models.

## Abstract

Light electroweakinos, the neutral and charged fermionic supersymmetric partners of the Standard Model $\mathrm{SU}(2)\times\mathrm{U}(1)$ gauge bosons and of the two $\mathrm{SU}(2)$ Higgs doublets, are an important target for searches for new physics with the Large Hadron Collider (LHC). However, if the lightest neutralino is the dark matter, constraints from direct dark matter detection experiments rule out large swaths of the parameter space accessible to the LHC, including in large part the so-called "well-tempered" neutralinos. We focus on the Minimal Supersymmetric Standard Model (MSSM) and explore in detail which regions of parameter space are not excluded by null results from direct dark matter detection, assuming exclusive thermal production of neutralinos in the early universe, and illustrate the complementarity with current and future LHC searches for electroweak gauginos. We consider both bino-Higgsino and bino-wino "not-so-well-tempered" neutralinos, i.e. we include models where the lightest neutralino constitutes only part of the cosmological dark matter, with the consequent suppression of the constraints from direct and indirect dark matter searches.