Superheavy Dark Matter from String Theory

TL;DR

This paper proposes that string theory models with late-time modulus domination can naturally produce superheavy neutralino dark matter, potentially explaining ultra-high-energy neutrino observations.

Contribution

It introduces a mechanism where early matter domination dilutes dark matter, allowing for superheavy neutralinos consistent with string compactifications.

Findings

Dark matter abundance can be diluted by modulus-driven matter domination.

Superheavy neutralino dark matter with mass around 10^{10}-10^{11} GeV is viable.

This mass range could explain ultra-high-energy neutrino detections.

Abstract

Explicit string models which can realize inflation and low-energy supersymmetry are notoriously difficult to achieve. Given that sequestering requires very specific configurations, supersymmetric particles are in general expected to be very heavy implying that the neutralino dark matter should be overproduced in a standard thermal history. However, in this paper we point out that this is generically not the case since early matter domination driven by string moduli can dilute the dark matter abundance down to the observed value. We argue that generic features of string compactifications, namely a high supersymmetry breaking scale and late time epochs of modulus domination, might imply superheavy neutralino dark matter with mass around $10^{10}-10^{11}$ GeV. Interestingly, this is the right range to explain the recent detection of ultra-high-energy neutrinos by IceCube and ANITA via dark matter decay.