Constraints on small-scale primordial power by annihilation signals from extragalactic dark matter minihalos

TL;DR

This paper investigates how gamma-ray and neutrino signals from extragalactic dark matter minihalos can constrain the primordial power spectrum on small scales, considering different assumptions about minihalo destruction.

Contribution

It provides a detailed analysis of constraints on small-scale primordial power using annihilation signals, accounting for various dark matter properties and destruction scenarios.

Findings

Constraints depend on annihilation modes, dark matter mass, and cross section.

Assumes delta-function primordial spectrum for analysis.

Provides both conservative and optimistic bounds on primordial power.

Abstract

We revisit constraints on small-scale primordial power from annihilation signals from dark matter minihalos. Using gamma rays and neutrinos from extragalactic minihalos and assuming the delta-function primordial spectrum, we show the dependence of the constraints on annihilation modes, the mass of dark matter, and the annihilation cross section. We report both conservative constraints by assuming minihalos are fully destructed when becoming part of halos originating from the standard almost-scale invariant primordial spectrum, and optimistic constraints by neglecting destruction.