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Physicists Identify Possible New Particle Behind Dark Matter
sciencehabit writes: Like cops tracking the wrong person, physicists seeking to identify dark matter — the mysterious stuff whose gravity appears to bind the galaxies — may have been stalking the wrong particle. In fact, a particle with some properties opposite to those of physicists' current favorite dark matter candidate — the weakly interacting massive particle, or WIMP — would do just as good a job at explaining the stuff, a quartet of theorists says. Hypothetical strongly interacting massive particles — or SIMPs — would also better account for some astrophysical observations, they argue.
I always thought that WIMP (Windows IIS MsSQL PHP) was the opposite of LAMP (Linux Apache MySQL PHP)?
If the force carriers for ordinary matter are called bosons...
Then would the force carriers for SIMPs be called...SIMPsons?
(T>t && O(n)--) == sqrt(666)
No one has yet lost any money betting against solutions for dark matter, so I am not going to get very excited about SIMPs (which, of course, are not really that new an idea anyway). Wait for it to get poked and prodded for a while, and then we'll see.
Then you will be relived that there is still just a little breathing room for MACHOS.
Not only are they inventing a new particle, but a new force as well ? Which is needed to explain how the new particles behave ?
Really this seems to be nothing more than an attempt to create an explanation that doesn't make predictions and is as removed from testability as possible.
No, that would be sterile neutrinos.
If you don't postulate some conjecture and start deriving all the required properties these particles are supposed to have, it's harder to find the proper experimental evidence you need to be looking for.
While everything you write is true, you leave out the actual importance of funding this: If SIMPS can be found, examination of their behavior in interactions would tend to prove or disprove fundamental ideas of the standard model.
That's my take on this all, anyway.
NB: I have been wrong before.
No one has "identified" anything. This is a paper with a proposal, an idea, a hypothesis. Behind it lie a rather gigantic pile of assumptions and parameters to fit the data. It's long been speculated that Dark Matter may not be simple, but rather could be as complicated as the visible spectrum (which contains electrons, photons, atoms, and the entire periodic table). But there's a huge problem with making predictions in a strongly interacting theory: you generally can't. "Strong interactions" mean that most computations do not converge. For instance we cannot, from first principles, calculate the mass of any atomic nuclei.
So this means the "dark matter sector" contains essentially a whole periodic table of stuff, and we're hopelessly unable to compute anything. This paper in particular ignores the possibility of bound states (e.g. atoms, mesons, etc) in the dark matter sector, which IMHO is just silly especially with strong interactions.
1^2=1; (-1)^2=1; 1^2=(-1)^2; 1=-1; 1=0.
Not only are they inventing a new particle, but a new force as well ? Which is needed to explain how the new particles behave ?
Really this seems to be nothing more than an attempt to create an explanation that doesn't make predictions and is as removed from testability as possible.
No, that would be sterile neutrinos.
There's another candidate for dark matter but if I understand things correctly it's ruled out because of the needed distribution.
Then what is it that keeps stealing one of my socks?
I got to the chocolate box before you, that's why the hard ones have teeth marks.
Everyone is looking at the WIMPs or SIMPs. But what about the BLIMP in the middle of the room?
Does anyone know what the "strongly" in SIMP means? If this means "Interact via the strong force", that could make some sense. It doesn't seem to mean "interact strongly with normal matter". If also seems to me quite likely that dark matter could interact (with other dark matter) by some new force that ordinary matter simply ignores (though anything that acts like friction is ruled out).
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The new particle is called the wildcardion. It plugs gaps in theories nicely.
Table-ized A.I.
There's plenty of direct evidence for them. We've observed huge (galaxy scale) gobs of something that can't be matter as we know it but has mass.
That long list of complex properties is what that something would have to have in order to explain the direct observations. And yeah, it's got to be pretty exotic and it proving hard to nail down exactly what it is.
So your postulation is that a theory which explains an enormous number of observations must be wrong because one group of observations... er, wait, what the hell are you saying?
The world's burning. Moped Jesus spotted on I50. Details at 11.
May I suggest a more generic name that doesn't have to be changed every five minutes?
Physically Interacting Massive Particles
The name will probably be shortened at some point.
I come here for the love
I understand the neutrino was theorized before discovery, but I just read the article and the chain of properties either WIMPs or SIMPs need to have, and they seem overly complex for something that there is no direct evidence for. Of course I am not a physicist. Just seems like we need better data collection of anomalous particle behaviors before investing much faith in such conjectures. Granted these theories could guide future experiments, but perhaps just sometimes theory gets a little too far ahead of experimental evidence.
Well, there is lots of evidence for something out there. This something, after coming up with other options and rejecting them through testing, must not interact with electromagnetic forces to a degree we can detect and have mass. Thus the "dark" and "matter". I am pa physicist and what you aren't seeing when you read these articles is a lot of math. It's complicated because physics at this level is really complicated and to come up with these hypothesis, they have to come up with something that fits what we already know about matter and the universe. That's going to involve a lot of graduate level mathematics and physics that describe a world that even physicists have a hard time wrapping their heads around. That's how particles get predicted, the math works out that way, and physics without the math is just philosophy. Sometimes you end up with something like string theory where the math works out (or seems to) but it can't be easily tested. At least these options can be tested.
Don't worry. You're a fine mixture of baryons and leptons. Any WIMPs or SIMPs are just along for the ride.
This article is a bit frustrating in that they haven't actually discovered a dark matter particle—they've just come up with a new idea for what it might look like. So it's not even a virtual particle. It's a hypothetical particle. But interesting nevertheless...
Because clicks is money.
If SIMPS can be found, examination of their behavior in interactions would tend to prove or disprove fundamental ideas of the standard model.
Yes, but that's what they said about WIMPS, too, and look where that has gone so far. (Pretty much nowhere.)
Hey, if I come up with some complex theory postulating DUMPs (Dubious Universal Massive Particles), can I get funding too? After all, proving their existence would force major changes to the standard model.
Yes, yes and yes. That's exactly why I concentrated on "funding": The politics of it are critical. Lots of hypotheses exist, but few get to be funded and none without extensive peer review by proven fundraisers.
It's a bit like The Movies in that there are lots of screenplays around, but only the ones producers think will turn a profit or an Oscar get produced.
I tried to be non-cynical in my post.
This is how science works.
It's not pretty, so you don't have to like it, but your not liking it is not a valid criticism.
That's one way to work, and usually the most popular because much of the theoretical work is done by grad students hoping to get a PhD out of what they find. The other way is to collect as much data about the situation as you can so that you can narrow down the possible explanations. Of course, that way rarely leads to a PhD, so it's not used very often. Quite understandable.
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As long as they don't come up with anything like YOG-SOTHOTH, I think we're fine
XDInd
So if the dark matter would just get out of the way, we could see this new particle ALOT better, right?
(the above question pretty much sums up my knowledge on this subject)
" no direct evidence for"
Where do you think that chain of properties comes from?
the Scarlet Pimpernel
This was one thing I didn't quite grasp when I first hit particle physics in college. It really did seem like many things were invented to explain experiments..and thus they explained experiments.
PS: I don't reply to ACs.
Dark Matter Core Defies Explanation
http://www.nasa.gov/mission_pa...
Of course I admit I am a little biased in my analysis above, because my own theory actually predicts this lensing effect and doesn't even require any new fictitious or magic particles to do it. When the Abell 520 survey came out it merely confirmed my hypothesis of how the physics actually works at the quantum level.
This hunt for "Dark Matter" really reminds me of the hunt for "Aether" way back when.
If the large scale structures of the Universe are not matching to how our theories say they should then maybe, rather than just looking for voodoo particles, we should also be asking ourselves seriously why we are assuming that our current theories are totally correct.
One thing that has bothered me about all the dark matter theories I have heard; if dark matter is only affected by gravity then what keeps it from all just collapsing into singularities?
I am pretty sure the first place you should search for DUMPs would be around Uranus. I'm not an astrophysicist though!
There's plenty of direct evidence for them.
There is no direct evidence of them. If there were, we wouldn't be having this discussion at all.
We've observed huge (galaxy scale) gobs of something that can't be matter as we know it but has mass.
They have not been observed. They have merely been inferred from the behaviour of things which have been observed. However, there are other possible explanations of those phenomena.
Modified Newtonian Dynamics explains it all.
Not only are they inventing a new particle, but a new force as well ? Which is needed to explain how the new particles behave ?
If dark matter particles interacted with any of the known forces (apart from gravity), they'd interact with ordinary matter and we'd be able to see them -- in other words, they wouldn't be dark. Whatever dark mater is made of, it almost certainly involves a new and undiscovered class of particles. Most likely particles in that new class will couple to each other in new ways -- which is another way of saying they experience new forces.
Really this seems to be nothing more than an attempt to create an explanation that doesn't make predictions and is as removed from testability as possible.
Many of the less exotic ideas have been eliminated by experiment. Negative results don't make good headlines, but much progress has been made on the search for dark matter and the number of possible theories has been greatly reduced. There is a real need for new ideas of this type.
I think that dark matter is made of a yet to be discovered material called math-errorium. You'll never guess why it hasn't been discovered yet.
"can't be easily tested"..? Nonsense, there is NO test. String theory isn't a theory as it isn't testable.
Not only are they inventing a new particle, but a new force as well ? Which is needed to explain how the new particles behave ?
If dark matter particles interacted with any of the known forces (apart from gravity), they'd interact with ordinary matter and we'd be able to see them -- in other words, they wouldn't be dark. Whatever dark mater is made of, it almost certainly involves a new and undiscovered class of particles. Most likely particles in that new class will couple to each other in new ways -- which is another way of saying they experience new forces.
Really this seems to be nothing more than an attempt to create an explanation that doesn't make predictions and is as removed from testability as possible.
Many of the less exotic ideas have been eliminated by experiment. Negative results don't make good headlines, but much progress has been made on the search for dark matter and the number of possible theories has been greatly reduced. There is a real need for new ideas of this type.
Or it might be time to start looking at other things entirely. Especially seeing as there has already been a considerable amount of work on finding 5th forces both attractive and repulsive When new theories start contradicting experimental data or start making statements that are untestable, at some point you have to drop back and say you have been barking up the wrong tree.
No, we have direct evidence of gravitational anomaly.
And new particles aren't the only game in town. Revised properties of gravity (TeVeS) are still candidates as there has yet to be irrefutable evidence against them, and given our continuing inability to directly observe said novel particles...
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Or it might be time to start looking at other things entirely. Especially seeing as there has already been a considerable amount of work on finding 5th forces both attractive and repulsive When new theories start contradicting experimental data or start making statements that are untestable, at some point you have to drop back and say you have been barking up the wrong tree.
I'm not sure what you're getting at. Science follows a simple recipe: observe, predict, test. We observe that galaxies rotate in a manner that cannot be accounted for by our existing understanding of gravity and matter. A whole bunch of predictions have been made according to different ideas about how to account for galactic dynamics, from gas clouds to black holes to brown dwarfs to modified gravity to exotic particles. From time to time somebody comes up with a new idea to add to the list. Those predictions are being tested and eliminated, and so far the one that's holding up best involves exotic particles. You can be sure the more prosaic possibilities were studied first, but it turns out they have not done a good job in matching observations. But it will take time any many experiments to uncover the truth. Meanwhile we will continue to bark up all the trees that are still standing, and search for new ones to climb.
I don't think we are assuming our current theories are totally correct, otherwise we wouldn't be looking for new physics (in the form of dark matter particles) to explain what we're seeing. Signs tend to indicate though that out current mode of thinking is correct but incomplete, as opposed to being completely wrong, which is why we're not throwing out everything and starting again from scratch.
These days, the data comes from high-energy interactions, and often involves highly improbable events. If you don't already know what to look for, you will have to slow down and analyze every event. If you do know what to look for, you can dial up the frequency of events tremendously, paying close attention only to the ones that surprise you in some way. This cuts observation times from well beyond human lifespans, to a matter of a year or two. It makes them practical.
How is the Riemann zeta function like Trump rallies? Both have an endless number of trivial zeros.
The Real Reason Dark Matter Can't Be Seen
The reason scientist can't find dark matter is that they're not looking in the right place. As soon as they look it is not dark matter but normal matter. This is because the Universe is very much like a game simulation in the computer where it only displays what you are looking at, not the things you're not looking at. This selective display saves computational resources allowing a higher, more realistic frame rate. Although the objects aren't displayed they still have to be accounted for in terms of gravitational and other force calculations because they are there, right? Now in the real Universe there are many people all looking in many directions, much like a multiuser game, so many different places are being displayed. Yet, still not all of the Universe has observers at the same time because there just aren't enough people looking or, as the case often is, they're looking at the same think like the Kashardians or a soccer game. The result is that even with the trillions of trillions of trillions of observers in the Universe not all parts of the Universe are being observed at any given moment. These unobserved portions are simply not displayed. That's where the Dark Matter is. If you look really quickly, oops, you looked and it got displayed so now it's no longer Dark Matter...
As long as the evidence fits, the theory sits.
Yes, either General Relativity is wrong (and Dark Matter non-existent), or the Standard Model of Particle Physics is wrong (for failing to predict Dark Matter), or the assumptions made by cosmologists are wrong (and Dark Matter is normal matter in an unexpected configuration). Either way, the Dark Matter data is legitimate data that will help us fill in the hole in our understanding.
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"The Search for Dark Matter - Professor Carolin Crawford
https://www.youtube.com/watch?...
If you are interested in astronomy you should check out the other videos of her from Gresham College. After Neil deGrass Tyson she's the only other person that makes me - who is only mildly interested in the subject - want to watch such hour log lectures all the way to the end. In other words: She's darn good at this!
Revised properties of gravity (TeVeS) are still candidates
Nope, not for a long time. Revised gravity theories still require some amount of dark matter to explain current observations, which makes them the by far worse option.
Wasn't there an article years ago about a theoretical test that only required a particle accelerator the size of Mars' orbit?
TBF, I think that would still qualify as "testable, just not with current technology".
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I believe that there are three possibilities here :
1.) A particle that interacts with normal matter via only the strong force, but evades the mass / cross section ratio limits on dark matter in some fashion.
2.) Matter that interacts with normal matter via all the usual forces, but evades the mass / cross section ratio limits on dark matter in some fashion. (Quark nuggets and primordial black holes fall into this category.)
3.) A particle that "strongly" interacts only with similar particles, by not the strong force, but by some new force.
I believe the present SIMPs are case number 3, that case number 2 aren't generally called "SIMPs", but case number 1 definitely has been so called; case number 1 particles have been significantly constrained in the past.
Modified Newtonian Dynamics explains it all.
In galaxies, yes. In interacting galaxy clusters, like the Bullet Cluster, it has problems. (If you are interested, you should look at the papers that cite this one - there has been a long argument on the Bullet Cluster and MOND, and Milgrom certainly isn't convinced, but my opinion is MOND is in trouble or is incomplete on these large scales.
Do you have any refrence for that assertion? The lensing clearly show actual filiments of higher redaction which would be a completly unnatural static formation for matter to arrange itself in. There is no natural laws of physics that could account for this to my knowledge. Please expand on your assertion, as I would certainly like to know more if there is any real evidence.