Dark matter may be hiding in a fifth dimension: Study
A new study published in The European Physical Journal C suggests that dark matter might come from a particle connected to a fifth dimension. The research is the first to fully use the "warped extra dimension" (WED) model to explain what dark matter could be.
The scientists, from Spain and Germany, say the current standard model of physics cannot explain everything we see in the universe. It cannot describe dark matter or answer why some particles, like the Higgs boson, are much lighter than expected, says Popular Mechanics.
"[T]here are still some questions which do not have an answer within the [standard model of physics]," the researchers wrote. "One of the most significant examples is the so-called hierarchy problem, the question why the Higgs boson is much lighter than the characteristic scale of gravity."
The study builds on the WED model, first introduced in 1999 by physicists Lisa Randall and Raman Sundrum. Their idea was that the universe could have a hidden, curved extra dimension. This "warping" might help explain why gravity seems weaker than the other fundamental forces.
In the new paper, the scientists suggest that certain particles, called fermions, could travel through "portals" into this fifth dimension. Inside that space, these particles could create what they call a "dark sector."
"[The standard model of physics] cannot accommodate some other observed phenomena. One of the most striking examples is the existence of dark matter," the scientists wrote. "We know that there is no viable [dark matter] candidate in the [standard model of physics], so already this fact asks for the presence of new physics."
The researchers propose that fermions pushed through a "portal" into the fifth dimension might behave like the invisible matter that makes up most of the universe.
Testing this theory would require powerful gravitational wave detectors that can sense signals from such hidden dimensions. The researchers said the answer to the dark matter puzzle "could be lurking around the corner," as new detectors are being built around the world.