Self-Interacting Dark Matter from the Hidden Heterotic-String Sector

TL;DR

The paper investigates self-interacting dark matter (SIDM) formed from hidden-sector glueballs arising in heterotic-string constructions. It argues that a hidden non-Abelian gauge group with vector-like matter, decoupling at a high scale, yields lightest glueballs with a confinement scale $\Lambda_h$ around 1 GeV, providing strong self-interactions while remaining SM-inert via heavy-mediator operators. Cosmological viability requires that the hidden sector energy density be generated after inflation through higher-dimensional operators with scale $M_S$, which constrains the reheating temperature and links $\Lambda_h$ to the UV spectrum. A renormalization-group analysis demonstrates regions of parameter space (notably with SU(2) hidden groups and intermediate-scale vector-like matter) in which $\Lambda_h\sim 1$ GeV can be achieved, and several realistic free-fermionic string models (NAHE-based) can realize such hidden sectors. Overall, the work ties SIDM phenomenology to plausible string-derived hidden sectors and outlines the cosmological and UV-scale requirements for feasibility.

Abstract

It has been suggested recently that self-interacting dark matter fits better the observational characteristics of galaxy dynamics. We propose that the self-interacting dark matter is composed from the glueballs of the hidden sector non-Abelian gauge group, while the hidden matter states exist in vector-like representation and decouple from the light spectrum. It is shown that these glueballs are semi-stable with the life-time larger than the present age of the Universe, if their mass is 1 GeV or less. The constraint on their abundance today suggests that the energy was stored in the hidden sector soon after inflation. This imposes an upper limit on the reheating temperature. We further study the naturalness of this scenario in the context of the free-fermionic string models and point out a class of such models where the self-interacting dark matter from the hidden sector is indeed plausible.