One-loop corrections to neutralino-stop coannihilation revisited

TL;DR

This paper revisits one-loop SUSY-QCD corrections to neutralino-stop coannihilation, highlighting their significant impact on relic density predictions within the MSSM, and discusses technical improvements over previous studies.

Contribution

It provides the first detailed analysis of the full NLO SUSY-QCD corrections to neutralino-stop coannihilation and its interplay with neutralino-pair annihilation.

Findings

Corrections significantly affect the total (co)annihilation cross section.

Numerical impact on neutralino relic density is substantial.

Improved technical methods enhance accuracy of theoretical predictions.

Abstract

We discuss the ${\cal O}(\alpha_s)$ supersymmetric QCD corrections to neutralino-stop coannihilation into a top quark and a gluon in the Minimal Supersymmetric Standard Model (MSSM). This particular channel can be numerically important in wide ranges of the MSSM parameter space with rather light stops. We discuss technical details such as the renormalization scheme and the phase-space slicing method with two cutoffs. We also comment on improvements with respect to earlier works on the given process. Further, we study for the first time the phenomenologically very interesting interplay of neutralino-stop coannihilation with neutralino-pair annihilation into quark pairs taking the full next-to-leading order SUSY-QCD corrections into account. We demonstrate that the numerical impact of these corrections on the total (co)annihilation cross section and finally on the theoretically predicted neutralino relic density is significant.