New Constraints on Primordial Minihalo Abundance Using Cosmic Microwave Background Observations

TL;DR

This paper uses WMAP-7 data to place new constraints on the abundance of primordial mini-halo objects formed during early cosmological epochs, focusing on their impact on dark matter annihilation and cosmic evolution.

Contribution

It provides the first constraints on MCHO abundance during the e+ e- annihilation phase using cosmic microwave background data.

Findings

2σ constraint: MCHO abundance less than 10^{-4} for dark matter masses 1 GeV to 1 TeV.

Constraints improve understanding of early universe structure formation.

Limits on dark matter annihilation effects from primordial mini-halos.

Abstract

It was proposed that the massive compact halo objects (MCHOs) would be produced during an earlier epoch of cosmology if the density perturbations are between $3 \times 10^{-4}$ and 0.3. Then these objects can accrete dark matter particles onto them due to their high density. If the dark matter is in the form of the weakly interacting massive particles, the MCHOs can have a significant effect on the evolution of cosmology due to the dark matter annihilation within them. Using the WMAP-7 years data, we investigated the constraints on the current abundance of MCHOs ($f_{MCHOs}$) formed during the $e^{+} e^{-}$ annihilation phase transition. We have found that the $2\sigma$ constraint is $f_{MCHOs} \lesssim 10^{-4}$ for dark matter masses in the range between 1 GeV and 1 TeV.