There may be a 'Fifth Dimension'

I am now confused as to what I dimension I had been listening to.

Futurism.Com:

A team of German and Spanish scientists says they've found a "natural explanation" for dark matter and other unresolved scientific mysteries — but their work depends on the existence of a new theoretical subatomic particle and an entire fifth dimension of the universe.

The new particle, a yet-undiscovered type of fermion, would be able to traverse this new dimension and bind dark matter to the luminous matter that makes up everything in the universe we can see or touch, Motherboard reports, in a way that doesn't contradict any of the other models we have on how dark matter behaves. It's seems a bit far-fetched — physicists creating new rules for the universe in order to explain their own theory — but if it pans out, it could vastly improve our understanding of the cosmos.