Decaying dark matter with heavy axino

TL;DR

This paper proposes a model where a heavy axino decays into a new dark matter candidate and MSSM particles, allowing for a calculable dark matter abundance and compatible decay lifetimes with astrophysical constraints.

Contribution

It introduces a new decaying dark matter scenario involving heavy axino decay within supersymmetry, with a calculable abundance and suppressed interactions.

Findings

Heavy axino decay can produce dark matter with the correct abundance.

Decay lifetimes of 10^{27} seconds are compatible with astrophysical bounds.

A diagrammatic method for suppression factors is developed.

Abstract

A TeV scale decaying dark matter chiral multiplet N is introduced in addition to the minimal supersymmetric standard model(MSSM). For a calculable abundance of N, we introduce heavy axino decaying to N and MSSM particles including the lightest supersymmetric particle(LSP). In the scenario that heavy axino, once dominating the energy density of the universe, decays after the LSP decouples, it is possible to estimate the relative cosmic abundances of N and the LSP. Dimension 6 interactions allow the lifetime of the fermionic or the bosonic superpartner of N in the 10^{27} s range to be compatible with the recent astrophysical bounds. A diagrammatic strategy obtaining a suppression factor 1/M^2 is also given.