The dipole formalism for massive initial-state particles and its application to dark matter calculations

TL;DR

This paper generalizes the dipole subtraction method to include massive initial states in SUSY QCD, enabling more precise and automated dark matter relic density calculations at NLO.

Contribution

It provides a full extension of the dipole subtraction formalism to massive initial states in SUSY QCD, with explicit dipole functions and application to dark matter processes.

Findings

Validated the method against phase space slicing results.

Facilitated future automation of dark matter relic density calculations.

Enhanced precision in theoretical predictions for dark matter models.

Abstract

The dark matter abundance plays a crucial role in the determination of the valid parameter space of models both in the case of a discovery of dark matter and in the context of exclusion limits. Reliable theoretical predictions of the dark matter relic density require technically demanding precision calculations, which were so far limited in their automation due to challenges in the treatment of infrared divergences appearing in higher order calculations. In particular, massive initial states need to be considered in early Universe computations, so that the known dipole subtraction methods could not be directly exploited. We therefore provide a full generalization of the dipole subtraction method by Catani and Seymour to supersymmetric (SUSY) QCD with massive initial states. All dipole splitting functions and their integrated counterparts are given explicitly for four different dimensional schemes. To showcase their application, we apply our results to dark matter (co)annihilation processes in the context of the minimal supersymmetric Standard Model. We also demonstrate the accuracy of the dipole method by comparing our numerical results with those obtained with the phase space slicing method. Our analytical results will facilitate future automation of dark matter abundance calculations at next-to-leading order for both SUSY and non-SUSY models.