August 12, 2013
Is Higgs Boson The Source Of Dark Energy?
John P. Millis, PhD for redOrbit.com - Your Universe Online
For the better part of two decades, the greatest fundamental question facing physics and cosmology has been, quite simply, what is dark energy? Detailed observations of galaxies in our Universe reveal the expansion of the Universe is accelerating. Even after accounting for all of the normal matter, radiation, and even the theorized dark matter out there, there still simply isn't enough "stuff" to explain the dynamics of the expanding universe.
Over the years, a number of theories have been suggested offering potential explanations as to the origins of this dark energy, including some that pose perhaps dark energy is not energy at all, but instead our theory of gravity needs to be tweaked and revised.
A new theory proposed by Arizona State’s Lawrence Krauss and James Dent of University of Louisiana-Lafayette suggests perhaps dark energy is created by interactions of exotic particles. Their work centers on the Higgs Boson – the particle manifestation of the Higgs field theorized to impart the property we call “mass” on particles as they pass through the field – and its interactions with other theorized particles expected to exist at energy scales beyond that of even the Higgs, referred to as the Grand Unified Scale where the electromagnetic, weak, and strong forces converge.
"We demonstrate that the simplest small mixing, related to the ratios of the scale at which electroweak physics operates, and a possible Grand Unified Scale, produces a possible contribution to the vacuum energy today of precisely the correct order of magnitude to account for the observed dark energy," Krauss explained. "Our paper demonstrates that a very small energy scale can at least be naturally generated within the context of a very simple extension of the standard model of particle physics."
There are many aspects to current dark energy theory that scientists are struggling to understand – such as its origin, its scale, and why it has such a specific value. But the theory proposed by Krauss and Dent pinpoints a very specific progenitor for the dark energy field, something that eludes some other theories.
"Our paper makes progress in one aspect of this problem," said Krauss, a Foundation Professor in Arizona State University's School of Earth and Space Exploration and in Physics, and the director of the Origins Project at ASU. "Now that the Higgs boson has been discovered, it provides a possible 'portal' to physics at much higher energy scales through very small possible mixings and couplings to new scalar fields which may operate at these scales.
"The deeper problem of why the known physics of the standard model does not contribute a much larger energy to empty space is still not resolved," says Krauss.