Neutralino dark matter in mSUGRA/CMSSM with a 125 GeV light Higgs scalar

TL;DR

This paper analyzes how recent Higgs mass measurements constrain neutralino dark matter scenarios in the mSUGRA/CMSSM model, highlighting the viability of the focus-point region and implications for detection experiments.

Contribution

It provides updated constraints on neutralino dark matter in mSUGRA/CMSSM considering a 125 GeV Higgs, emphasizing the shift to the focus-point region and implications for detection prospects.

Findings

Stau and stop co-annihilation mechanisms are nearly eliminated.

A-resonance annihilation is ruled out in mSUGRA.

Focus-point region remains viable for neutralino dark matter.

Abstract

The minimal supergravity (mSUGRA or CMSSM) model is an oft-used framework for exhibiting the properties of neutralino (WIMP) cold dark matter (CDM). However, the recent evidence from Atlas and CMS on a light Higgs scalar with mass m_h\simeq 125 GeV highly constrains the superparticle mass spectrum, which in turn constrains the neutralino annihilation mechanisms in the early universe. We find that stau and stop co-annihilation mechanisms -- already highly stressed by the latest Atlas/CMS results on SUSY searches -- are nearly eliminated if indeed the light Higgs scalar has mass m_h\simeq 125 GeV. Furthermore, neutralino annihilation via the A-resonance is essentially ruled out in mSUGRA so that it is exceedingly difficult to generate thermally-produced neutralino-only dark matter at the measured abundance. The remaining possibility lies in the focus-point region which now moves out to m_0\sim 10-20 TeV range due to the required large trilinear soft SUSY breaking term A_0. The remaining HB/FP region is more fine-tuned than before owing to the typically large top squark masses. We present updated direct and indirect detection rates for neutralino dark matter, and show that ton scale noble liquid detectors will either discover mixed higgsino CDM or essentially rule out thermally-produced neutralino-only CDM in the mSUGRA model.