We still haven't found the Higgs boson, the hypothetical particle that explains why other particles possess mass. But that might not be the only cosmic mystery the Higgs can solve. It could also explain how the universe got its shape.
That's the theory put forward by researchers at Switzerland's École polytechnique fédérale de Lausanne, or EPFL. They argue that the Higgs boson might allow us to account for inflation, the otherwise unexplained process in which the early universe grew by a factor of at least 10^26 in an instant. It's not a universally accepted idea, even among physicists and cosmologists, but it seems to be the best way to account for the uniformity of the modern universe. (For an excellent, comprehensive primer on inflation, check out this post by our own Dr. Dave Goldberg.)
Exactly what caused inflation is still up in the air, and that's where the EPFL physicsts believe the Higgs boson enters the picture:
In its first moments, the Universe was unimaginably dense. Under these conditions, why wouldn't gravity have slowed down its initial expansion? Here's where the Higgs boson enters the game – it can explain the speed and magnitude of the expansion, says Mikhail Shaposhnikov and his team from EPFL's Laboratory of Particle Physics and Cosmology. In this infant Universe, the Higgs, in a condensate phase, would have behaved in a very special way – and in so doing changed the laws of physics. The force of gravity would have been reduced. In this way, physicists can explain how the Universe expanded at such an incredible rate.
Here's where things get really interesting. The researchers found that, as this condensate form of the Higgs boson disappeared and the particles we know today took over, their equations permitted for the existence of a new, massless particle, which they've dubbed the dilaton. This particle is closely related to the Higgs, and shares many of its properties. But the dilaton is only similar to the Higgs - its properties happen to exactly describe what we observe with dark energy, the mysterious property or force that is causing the universe to accelerate its expansion.
The researchers had not set out to explain dark energy when they worked out what role the Higgs boson might have played in the expansion of the universe. Obviously, this is all strictly theoretical - particularly the dilaton - but the fact that their attempt to explain one cosmic mystery happens to also explain another is an encouraging sign that there may well be something to this. These are big claims, of course, and it's doesn't matter how elegant the equations are if we can't find any proof of these particles, but still...this is one hypothesis that's definitely work a closer look.
Via arXiv. Illustrations by EPFL.