SUSY-QCD corrections to stop annihilation into electroweak final states including Coulomb enhancement effects

TL;DR

This paper calculates detailed supersymmetric QCD corrections, including Coulomb effects, to stop-anti-stop annihilation into electroweak states, significantly impacting neutralino relic density predictions in the MSSM.

Contribution

It provides the first full $ ext{O}( ext{α}_s)$ SUSY-QCD correction calculations for these processes, incorporating Coulomb effects and analyzing their impact on relic density.

Findings

Radiative corrections can shift relic density predictions by tens of GeV.

Coulomb effects significantly enhance the annihilation cross sections.

Corrections surpass current experimental uncertainties in some parameter regions.

Abstract

We present the full $\mathcal{O}(\alpha_s)$ supersymmetric QCD corrections for stop-anti-stop annihilation into electroweak final states within the Minimal Supersymmetric Standard Model (MSSM). We also incorporate Coulomb corrections due to gluon exchange between the incoming stops. Numerical results for the annihilation cross sections and the predicted neutralino relic density are presented. We show that the impact of the radiative corrections on the cosmologically preferred region of the parameter space can become larger than the current experimental uncertainty, shifting the relic bands within the considered regions of the parameter space by up to a few tens of GeV.