WIMPless dark matter and the excess gamma rays from the Galactic center

TL;DR

This paper examines WIMPless dark matter models in relation to gamma-ray excesses, cosmic microwave background anomalies, and direct detection signals, highlighting the challenges in simultaneously explaining all observations within these models.

Contribution

It provides a comprehensive analysis of WIMPless dark matter models, assessing their ability to explain multiple astrophysical and experimental signals and constraints.

Findings

Scalar/vector WIMPless dark matter cannot explain all signals simultaneously.

Fermion WIMPless dark matter can marginally fit some signals with vector connector fields.

Scalar connector fields can account for the WMAP haze but may cause lepton flavor violation.

Abstract

In this paper we discuss the excess gamma rays from the Galactic center, the WMAP haze and the CoGeNT and DAMA results in WIMPless models. At the same time we also investigate the low energy constraints from the anomalous magnetic moment of leptons and from some lepton flavor violating decays. It is found that, for scalar or vector WIMPless dark matter, neither the WMAP haze nor the CoGeNT and DAMA observations could be explained simultaneously with the excess gamma rays from the Galactic center. As to fermion WIMPless dark matter, it is only marginally possible to accommodate the CoGeNT and DAMA results with the excess gamma rays from the Galactic center with vector connector fields. On the other hand, only scalar connector fields could interpret the WMAP haze concerning the constraints of anomalous magnetic moment of leptons. Furthermore, if there is only one connector field for all the charged leptons, some lepton flavor violating decays could happen with too large branching ratios severely violating the experimental bounds.