Physics

Hypothetical particle explains three major mysteries of the universe

Hypothetical particle explains...
A hypothetical particle called an axion could explain three different physics mysteries
A hypothetical particle called an axion could explain three different physics mysteries
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An artist's model of how oscillation of axions (black ball) in the early universe could have created more matter (colored balls) than antimatter
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An artist's model of how oscillation of axions (black ball) in the early universe could have created more matter (colored balls) than antimatter
New research has found that the distribution of mass in galaxy clusters can be explained by dark matter that's both fuzzy and in excited states
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New research has found that the distribution of mass in galaxy clusters can be explained by dark matter that's both fuzzy and in excited states

The Standard Model of particle physics does a decent enough job of explaining the universe, but it still has some holes in it. Now, a new study outlines how one hypothetical particle, the axion, may be the answer to three separate, massive mysteries of the universe – including why we’re here at all.

If it exists, the axion is said to be incredibly light – billions of times lighter than a proton – and have no electric charge. They should be floating around basically everywhere, but rarely interact with other matter. All of this makes them pretty hard to detect, which may be why we haven’t found direct evidence of them yet.

For the new study, researchers at the University of Michigan and the Institute for Advanced Study suggest that the axion could essentially have saved our universe from annihilating itself in the early days.

By all counts, the Big Bang should have produced matter and antimatter in equal measure. The problem is, if ever the two shall meet they’ll destroy each other in a burst of energy. That means that if there were equal amounts of matter and antimatter, they should basically have cancelled each other out long ago. But here we are today, in a universe filled with regular matter. Where all that antimatter went is one of the biggest mysteries in physics.

According to the researchers on the new study, axions may be the answer. The team suggests that in the early days of the universe, the axion field started to oscillate, and this motion would have created just a fraction more matter than antimatter. Even if the imbalance was one part in 10 billion, that would have left enough matter behind to form everything around us today.

The team named this mechanism “axiogenesis.” And the matter-antimatter asymmetry isn't the only problem that axions have been proposed to solve.

An artist's model of how oscillation of axions (black ball) in the early universe could have created more matter (colored balls) than antimatter
An artist's model of how oscillation of axions (black ball) in the early universe could have created more matter (colored balls) than antimatter

The axion was first hypothesized in 1977 by physicists Roberto Peccei and Helen Quinn, in order to plug a particular hole in the Standard Model. Neutrons don’t interact with electric fields – but they should. That’s because they’re made up of smaller particles called quarks, which are charged and do interact with electric fields. The question of why neutrons don’t interact with electric fields is known as (an extremely abridged version of) the strong CP problem.

Axions are thought to be able to switch off this interaction between neutrons and electric fields, effectively solving the conundrum. But that’s not all. A few years later and scientists have realized axions are also a handy explanation for dark matter.

Decades of astronomical observation has repeatedly shown that there’s more mass out there than just the stuff we can see. Galaxy clusters wouldn’t be able to hold themselves together under the gravity of just visible mass, and calculations suggest as much as 85 percent of matter is unaccounted for. This invisible mass is dubbed dark matter.

What exactly dark matter is has been debated for decades, with many different candidate particles being put forward. And one of the main contenders that keeps coming up is the axion. Get enough of them together in a pervasive field, and their extra mass could account for the odd gravitational effects attributed to dark matter.

Physicists have been hunting for evidence of axions for years, using experimental facilities that search for their rare interactions with neutrons or electromagnetism. So far, no sign of them has been detected, which is narrowing down the range of masses that they could potentially have.

And if they ever are found, it looks like they may be more valuable than we thought. Not only would we have found dark matter, but we could solve the strong CP problem and the matter-antimatter asymmetry in one fell swoop.

“The versatility of the axion in solving the mysteries of fundamental physics is truly amazing,” says Raymond Co, an author of the study. “We are thrilled about the unexplored theoretical possibilities that this new aspect of the axion can bring. More importantly, experiments may soon tell us whether the mysteries of nature truly hint towards the axion.”

The study is due to be published in the journal Physical Review Letters.

Sources: University of Michigan, Institute for Advanced Study

8 comments
Bob Stuart
I have never understood the matter-antimatter problem. If they turn each other to energy, wouldn't they just re-condense and do it again until a random odd number tipped the balance?
Cryptonoetic
"...the axion is said to be incredibly light – billions of times lighter than a proton – and have no electric charge." Sounds like a neutrino to me.
paul314
Is the axion the answer, or is it so versatile at being the solution to all these different problems because it's not constrained by having to exist?

@Bob Stuart: Without some independent influence (like axions) there is no random odd number. Every time an particle and and antiparticle meet, you get a photon, and every time a high-energy photon generates some matter, it generates a particle-antiparticle pair. You need something that asymmetrically sucks either particles or antiparticles out of the mix, or turns on into the other. (For example, if somehow magically primordial black holes preferentially absorbed only anti-protons.) As it is, the estimated asymmetry was pretty small.
Expanded Viewpoint
So much of this is just pure conjecture and speculations, it boggles my mind that anyone takes even one bit of this seriously!! If there was a "Big Bang" of anything, then from WHERE did all of that matter and energy come from? Where's the "family tree", so to speak?? What is the real origin point of the physical universe?? Oh, it just happened to suddenly decide on its own to exist one fine day, and voila! There it is, in all of its magnificent glory??
Where does space actually begin and end? What is on the other side of that border line/wall? How did space get here? We know for a fact that space does exist, and that we are operating in a space, so just how big is that space? How far does it reach out? How can there be so much matter all over the place with the incredible number of atoms that make all of it up, and they are the same everywhere you may care to look? Are any of the Elements different somewhere else?

Randy
bwana4swahili
"Get enough of them together in a pervasive field, and their extra mass could account for the odd gravitational effects attributed to dark matter."

Allowing for a minute variance in the gravitational constant could easily accomplish the same thing!
jgb
The heading says it all! A fake 'fact' is made up to fit a predetermined hypothesis. Just like evolution, where made-up models 'prove' the hypothesis eliminating the need for real scientifically determined answers. There must be no God irrespective of where the truth lies.
Yakov Dragunov
Everything, all particles have a use. Of what use is this one? However, since here it is postulated that axion fields create matter, then would the anti-axion which would need to exist for symmetry create space? Or a space field. Of course if that was so, then the anti-axion could be used to create warp drives and maybe stargates fed by wormholes. May even have six dimensional temporal effects. Three traditional directions defining a place with three time-like dimensions also mutually normal to each other to create a time field. Theorize that said 3-D temporal field traversable in any direction or combination of directions using any function discontinuous or not. Other theories suggest that spatial dimensions can become more timelike, so this process should aid that. The only prohibition for causality would be that all these dimensions are principal quantum numbers and no exact and congruent regressions along the path of an object defined on this f[dsx,dsy,dsz,dta,dtb,dtc] would be possible. IN here it is still possible to whack grandadies(ouch) but not one of the grand-daddies you find will be specifically YOUR grandaddy because your time travels will all land you in other universes or in yours but only forward of your time/space locus.
Pequod42
There is a problem here:"The team suggests that in the early days of the universe, the axion field started to oscillate, and this motion would have created just a fraction more matter than antimatter." The article lands here, with oscillations in the axion field creating matter and anti-matter, but the writer has never even described the relationship between the creation of matter and the axion field. This kind of theoretical speculation is fun. But explantions have to follow the rules of logic. Here at least one term is missing, and the lacuna shakes my faith a bit in everything else the writer says here.