Closing the Window on Strongly Interacting Dark Matter

TL;DR

This paper refines constraints on strongly interacting dark matter by analyzing cosmic ray interactions and Earth's heat flow, effectively closing the window on such particles up to very high masses.

Contribution

It introduces combined constraints from cosmic ray gamma rays and Earth's heat flow analysis, significantly narrowing the parameter space for strongly interacting dark matter.

Findings

Cosmic ray interactions constrain dark matter cross sections above a certain threshold.

Earth's heat flow analysis constrains cross sections below a certain threshold.

Combined constraints exclude strongly interacting dark matter up to 10^{17} GeV.

Abstract

Constraints are placed on the spin-independent interaction cross section of dark matter with regular matter by refining two methods. First, dark matter--cosmic ray interactions are considered, wherein cosmic ray protons collide with dark matter to contribute to the gamma ray sky. This constraint is developed using the NFW and Moore dark matter density profiles and new data from the Fermi gamma ray space telescope. Second, the Earth capture scenario is considered, wherein particles that are captured self-annihilate at Earth's center, thus adding to its internal heat flow. The constraint presented here is developed based on analysis of the drift time of dark matter particles through Earth, modeled as a core composed of iron and a mantle composed of oxygen with linear density gradients between layers. An analysis of the cosmic ray constraint (which rules out dark matter--regular matter interaction cross sections greater than its value) shows that it overlaps significantly with the Earth drift time constraint (which rules out cross sections smaller than its value), closing the window on strongly interacting dark matter particles up to a mass of about 10^{17} GeV when combined with other exclusions.