TSoDS #5: Dark Matter Take Another Shot On the Chin.

[Blue State Bandit]

Electron's shapeliness throws a curve at supersymmetry.

The Standard Model, long understood as incomplete, may have taken a big hit under observational experiments conducted by the ACME collaboration out of Harvard and Yale.

In research published in Science Express, the team reported the most precise measurement to date of the electron's shape, improving it by a factor of more than 10 and showing the particle to be rounder than predicted by some extensions of the Standard Model, including some versions of Supersymmetry. This theory posits new types of particles that help account, for example, for dark matter, a mysterious substance estimated to make up most of the universe.

Researchers said they have shown that the electron's departure from spherical perfection - if it exists at all - must be smaller than predicted by many theories proposing particles the Standard Model doesn't account for. If the electron's shape is too round, many of these theories will be proven wrong, they said.

Many variants of Supersymmetry predict a less round shape for the electron than the ACME team found experimentally. If the particles predicted by those versions of Supersymmetry existed, they would have caused greater deformation of the electron, researchers said.

The ACME project looked for a particular deformation in the electron's shape known as an electric dipole moment.

[enki23]

1. Since when does no SUSY mean no dark matter?

Dark Matter wasn't a concept somebody invented in order to explain SUSY.

[longship]

2. Because the least massive SUSY particles are prime dark matter candidates.

And this is not the first research that has had bad news for SUSY.

There are other posited dark matter ideas, though. Frank Wilczek's Axions, for instance.

But breaking the Standard Model would be big news. Physicists have been trying to do that for decades with no luck. It appears that somebody might have found some cracks in the theory. That's always a good sign because you pry them open and new science may reveal itself.

Then, there's Strings...
:crickets:

[Blue State Bandit]

10. Your right. DM was invented to explain expansion.

Lack of super-symmetry in this experiment decreases the likelihood that DM is anything more than a waste of computational time.

[caraher]

11. Not quite

Dark energy explains expansion. Dark matter acts, gravitationally, like ordinary matter - always attractive.

The mystery dark matter is supposed to explain is that galaxies seem to have more mass than their visible components would suggest, based on how fast stars on their peripheries move.

[enki23]

12. Not just that.

It's also needed to explain observed gravitational lensing, and fluctuations in the CMB that are explained by dark matter (dark gravity, whatever) which aren't explained by the "gravity is different in some parts of galaxies" theories like MOND.

[caraher]

13. True

But not expansion!

[Blue State Bandit]

14. Or.. that redshift measures speed, not relative distance, and those lensed objects...

and CMB flux have simpler explanations.

For instance, lensing can be a function of source EMR interacting with the magnetic field of the lensing body i.e. the galaxy in the foreground.
But primarily, many quasars that form the basis of the RS observations that "prove the need" for the existence of DM, are actually not behind the "lensing object" but connected to said objects via plasma filaments as observed in the near IR wavelength (.7 to 1 µm) photos of NGC 7603.

[longship]

3. The title is horrible.

Dark Matter is a real thing. It's not dark matter that took it on the chin, it's the physicists try to find out what the fuck dark matter is made of.

One of the main candidates was SUSY particles.

BTW, there's some five times more dark matter in the universe than matter we can detect directly. So this is a rather sticky wicket for both the theorists and the experimentalists.

We know it exists. We just don't know what the fuck the shit is.

Douglas Adams had the best conjecture that I've heard. Dark matter is made up of all the packing peanuts used to ship all the equipment to physicists to study dark matter.


Like Douglas, I love self-referencing statements.

[Blue State Bandit]

5. The only thing real about it is that it's dark.

Try looking in the Hydrogen Alpha band.

http://irsa.ipac.caltech.edu/data/SPITZER/LVL/

[longship]

6. Hydrogen Alpha from dark matter? Not likely.

On cellular network here. No broadband or cable here. So your link is not going to work for me.

On the hydrogen alpha thing...

Dark matter is dark because it does not interact via electromagnetism. That means there is no Hydrogen alpha lines, or any other EM spectrum emissions. It's why they call it dark matter.

It interacts by the weak nuclear force, and of course, by gravity. (AFAIK)

[mindwalker_i]

4. As far as we can tell, electrons are point-particles

Does this measurement pertain to the shape of the electric field around the particle? It doesn't make sense to talk about deformity of a point-particle. It's a friggin' point. You can't deform that.

As for dark matter, Andrew Thomas (http://www.ipod.org.uk/reality/) has a book out that posits that gravity becomes repulsive when measured on scales greater than the Schwartschild radius of the object in question. That pretty much means only the universe as a whole, so everything from grapes to galactic clusters would show attractive gravity. This is in his book "Hidden In Plain Sight (2)" and it's pretty cool!

[longship]

7. Re: Andrew Thomas...

I think what you are describing is dark energy, not dark matter. (Two horribly named physical properties, which are inevitably to be confused.)

[mindwalker_i]

8. You are partially correct

I was thinking of the dark energy aspects, but I think Thomas' theory also touched on dark matter as well. I'd have to reread it, but if I remember correctly, gravity would be modified slightly even in small regions like galaxies - enough to compensate for the apparent increase in mass that causes galaxies to not fly apart.

Relativity describes gravity as a warping of space in the presence of matter - actually I think it's energy. If this modified theory is accurate, then the warping of space is more complex, and becomes more of a convex bubble when taken at distances greater than the Schwartschild radius. It would still be concave at smaller distances. This doesn't make sense in my mind. It must be more complex still, since it doesn't make sense that space would be convex over a large distance but concave over shorter distances.

Still, the book is worth reading, as is his first book. It's definitely worth the dollar for the Kindle edition.

[BillionsNbillions]

15. Thomas's dark energy idea.

Its not that space is convex, or concave, Thomas, and most every other cosmologist say space is FLAT. I read that book as well, and it seems like Thomas is saying gravity works differently at large distances than small, but that is not what he meant. Thomas's whole idea rests on the idea of the Schwarzchild radius. Let's say the sun was squashed down until it created a black hole say a mile radius. If we could then instantaneously dump a one solar mass of matter into the black hole, the event horizon of the black hole would grow in radius so that the radius equaled the Schwarzchild radius. That energy that provides the increasing diameter is what Thomas says is the dark energy, from inside the black hole, space would have expanded. It all rests on the fact that any volume in the universe can be fully described by the 2-D boundary encapsulating that volume of space, the Holographic Principle.

How he surmises that our entire universe, with all of its empty space, has an event horizon similar to a black hole is because the Schwarzchild radius equation shows that as the radius of a black hole type of body increases, the average density decreases. A black hole that is 1.5 solar masses is incredibly dense, more matter than our solar system crammed into a ball only a mile or so in diameter, a density of millions of tons per cubic centimeter. A supermassive black hole containing billions of solar masses has the density of water because its radius is so much larger.

Now we go up to the size of the universe, and it appears that the universe is a bit smaller than the Schwarzchild radius, SR, meaning gravity is pushing the entire universe to expand to the size of the Schwarzchild radius. Then, after the universe expands to that SR it will oscillate past it, making it bigger than the SR, and then gravity will contract the universe, and once again it will oscillate the other direction to be smaller, and bounce back and forth until it hits equilibrium and is precisely the size of the SR. So we can see that its not distance that matters, its whether a region's given density and radius are larger or smaller than the Scwharzchild radius.

I did some calculating to see if there really was enough information in the universe to make it appear like we are in the inside of a black hole, and it turns out that it appears that the cosmic event horizon is fully packed with one unit of information per planck area, just like an ordinary black hole. I don't know why a lot of leading physicists pooh-pooh the idea that the universe is a black hole when it appears that our universe does in many ways seem to meet the mathematical criteria of a black hole, the two biggest being the SR and the fact that the density of information on the cosmic event horizon equals one unit of information per planck area. The only difference that I can see is that the universe is a 3-sphere black hole, and the black holes smaller than our universe are 2-spheres, but maybe they only look like 2-spheres from the outside, maybe on the inside they are all 3-spheres.

[emsimon33]

16. Thank you for your very informative comments

And...welcome to DU!

[caraher]

9. They're looking at its electromagnetic properties

Last edited Tue Dec 31, 2013, 05:44 PM - Edit history (1)

The paper is titled "Order of Magnitude Smaller Limit on the Electric Dipole Moment of the Electron." (I've linked the arxiv version; the full publication is behind a paywall.)

They've done an experiment to measure the electric dipole moment of the electron and set a new, lower upper limit on its value. Evidently this upper limit is lower than the dipole moment predicted by many theorists.

Interpreting the dipole moment in terms of shape is problematic. It's easy to show that a non-spherical extended object would necessarily have nonzero multipole moments (dipole, quadrupole, etc.). But it does not really follow that a nonzero electric multipole moment implies a non-spherical structure or any particular spatial "shape." This is just something written to make the research more accessible to a lay audience.

A similar case is spin. There's no good classical model for electron spin; any "reasonable" model of an extended, spinning electron that would explain its magnetic moment fails. Instead, we say it does have a spin and a magnetic moment because of essentially quantum effects, despite an electron having no measurable spatial extent. Similarly, the claim would be that an electron may have a nonzero electric dipole moment not because it has a nonspherical charge distribution over an extended region of space, but because of whatever effects these models predict might confer a dipole moment.