Mark Megahan
The dark matter physicists who hunt the elusive Axion know that the great thing about chaos is anything can happen. That gives them hope because looking for something that isn’t there is really tricky. Still, they say, it’s possible to pinpoint an invisible force.
What an axion is
Scientists over at Durham University and Kings College London have a new method to help in their search for missing “dark” matter. They’re on the trail of one particular species of the critter, “axion” dark matter. They call it a particle, then they start looking for sheets of the stuff.
That calls for a refresher course of quantum physics 101. A particle, like a photon of light for example, can also be a “wave” at the same time. Some particles, like the graviton, are not only particles and waves, they form sheets called “fields.”
Axions, it seems, exist in particle, wave, and sheet form as well. Dr. Francesca Chadha-Day and her colleagues used that to come out with a new outline for dark matter detection, as well as a renewed call for scientists to investigate the hypothetical particle.
“It is a very exciting time to be an axion physicist. Nobody yet knows the identity of dark matter,” she relates.
The hypothetical elementary particle was first alleged in 1977 “as part of the Peccei-Quinn theory that provided a possible solution to the strong CP problem.”
In that particular theory, “the axion explains why the strong interaction” obeys time-reversal symmetry. That’s the one which binds quarks in protons and neutrons.
The search for missing matter
By “searching for different possibilities,” Dr. Chadha-Day explains, “such as the axion, we hope to one day solve this mystery.”
Albert Einstein and his general theory of relativity have been proven correct to a whole string of decimal places. Since we know he’s right, either the universe is all wrong or there is a whole lot more matter out there than we can inventory.
Her team of researchers analyzed axion particles from a “mathematical perspective” and they “also posited how the hypothetical particles relate to the fundamental symmetries of the Standard Model of particle physics.”
They think this theoretical flavor of dark matter “behaves more like a field covering the universe than like individual particles.” What’s most important is the way it behaved in the split second following the big bang.
“In the early universe, the value of the axion field begins to oscillate back and forth. The energy stored in these oscillations is axion dark matter.” They found a way to look for the field using the particle variety. Their study came up with a potential method to detect interactions with the particles in the lab.
There’s a tiny chance that a photon passing through a magnetic field can turn into an axion. “With that in mind, astronomers might hone in on images of galaxies observed shining through magnetic fields.” The hope is that it will lead to “the long-sought detection of dark matter.“
