Primordial monopolium as dark matter

TL;DR

This paper explores Kaluza-Klein monopolium, a monopole-anti-monopole bound state, as a potential primordial dark matter candidate due to its weak electromagnetic interactions and gravitational effects.

Contribution

It introduces the concept of monopolium as a stable, electromagnetically inert bound state in Kaluza-Klein theories and analyzes its astrophysical detectability.

Findings

Monopolium interacts only gravitationally in free space.

Radiation from monopolium in magnetic fields is undetectably small.

Monopolium could be a candidate for primordial dark matter.

Abstract

The existence of monopoles is a characteristic signature of Kaluza-Klein multidimensional theories. The topology of these solutions is extremely interesting. The existence of a dipole solution, which we have associated to a monople-anti-monopole bound state, is the leitmotiv of this investigation. The dipole in its lowest energy state, which we here call also monopolium, is electromagnetically inert in free space interacting only gravitationally. Monopolium when interacting with time dependent magnetic fields acquires a time dependent induced magnetic moment and radiates. We have analyzed the most favorable astrophysical scenario for radiative monopolium and found that the amount of radiation is so small that is not detectable by conventional equipments. These findings suggest that Kaluza-Klein monopolium, if existent, would be a candidate for a primordial dark matter constituent.