Neutralino-stop co-annihilation into electroweak gauge and Higgs bosons at one loop

TL;DR

This paper calculates one-loop supersymmetric QCD corrections to neutralino-stop co-annihilation processes into electroweak and Higgs bosons, showing significant impact on dark matter relic density predictions in the MSSM.

Contribution

It provides the first detailed calculation of full O(alpha_s) corrections for these co-annihilation channels in the MSSM, including renormalization and infrared treatment.

Findings

Corrections significantly affect the neutralino relic density predictions.

Impact of corrections exceeds current WMAP experimental uncertainties.

Results refine the phenomenological MSSM parameter space analysis.

Abstract

We compute the full O(alpha_s) supersymmetric QCD corrections for neutralino-stop co-annihilation into electroweak gauge and Higgs bosons in the Minimal Supersymmetric Standard Model (MSSM). We show that these annihilation channels are phenomenologically relevant within the so-called phenomenological MSSM, in particular in the light of the observation of a Higgs-like particle with a mass of about 126 GeV at the LHC. We present in detail our calculation, including the renormalization scheme, the infrared treatment, and the kinematical subtleties to be addressed. Numerical results for the co-annihilation cross sections and the predicted neutralino relic density are presented. We demonstrate that the impact of including the corrections on the cosmologically preferred region of parameter space is larger than the current experimental uncertainty from WMAP data.