What if dark matter particles aren't WIMPs?
December 12th, 2008 By Miranda Marquit(PhysOrg.com) -- For years, many physicists have accepted that dark matter is composed of weakly interacting massive particles (WIMPs). The fact that WIMPs can naturally explain the amount of dark matter in the universe – left over from the Big Bang – has been described as the “WIMP miracle.”
Not everyone, though, thinks that this phenomenon represents an ironclad prediction that dark matter is made of WIMPs. “We know little about dark matter, since we can’t measure it directly,” Jonathan Feng tells PhysOrg.com. “But there are theories and models. WIMPs are attractive because they happen to appear in many popular theories of new particles and interactions. But what if there are other well-motivated possibilities for dark matter besides WIMPs?”
Feng, a physicist at the University of California, Irvine, worked with Jason Kumar (now at the University of Hawaii) to re-examine physics models to find additional possibilities for dark matter. Their work, published in Physical Review Letters and titled “Dark-Matter Particles without Weak-Scale Masses or Weak Interactions,” suggests that dark matter could be composed of heavier, strongly interacting particles, or even particles that are lighter and more weakly interacting than WIMPs.
“WIMPs are a very specific example of dark matter,” Feng continues, “but there is a broader class of particles. We found that some of the models also predicted the right amount of dark matter for the universe, but with dark matter that was much more strongly or weakly interacting than WIMPs. We are wondering if almost-exclusive attention for WIMPs is really warranted.”
Feng says that WIMPs are thought to be right around 100 GeV in mass. However, there is evidence that dark matter particles could be as light as 1 GeV. This puts them far below WIMP range. “An experiment called DAMA has been recording dark matter signals, and there is evidence that they are seeing light dark matter particles. We have perfectly good 1 GeV candidates,” he says, “and now we can accommodate such light particles.”
Some models seem to support a stronger degree of interaction between particles, Feng believes. In order to get to the level of dark matter we have in the universe now, though, these particles would have to be annihilating each other now. “These models imply that experiments looking for very energetic photons may be very promising.”
But the idea of WIMP-less dark matter gets a little more interesting than simply considering weaker or stronger dark matter candidates. Feng says that WIMP-less dark matter could provide some support for the idea of a hidden sector – a so-called shadow world. “There are theories that there is a shadow world behind ours. It is a mirror world that is like ours, but doesn’t interact with ours. With WIMP dark matter, that possibility is remote.”
“WIMP-less dark matter requires new forces that we don’t really know much about. If you could have evidence of this type of dark matter, it might be a hint that this shadow world exists.”
Mirror worlds and hidden sectors aside, Feng believes that his and Kumar’s findings warrant a close look. “Perhaps the millions of dollar spent on WIMPs is not the most productive way to use the money. This opens up a whole bunch of different avenues for discovering what dark matter is.”
More information: Jonathan L. Feng and Jason Kumar. “Dark-Matter Particles without Weak-Scale Masses or Weak Interactions.” Physical Review Letters (2008). Available online: http://link.aps.org/doi/10.1103/PhysRevLett.101.231301.
Copyright 2007 PhysOrg.com.
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Jun 22, 2009 |
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Excellent. Utterly excellent.
There are very interesting new gravity models that could cope with the behavior observed without these messy dark things...
What if dark matter doesn't exist?
hmmm
Enron accounting principles CAN be applied in other areas!
http://www.presto...ndex.htm
Well, if general realativity is at least a little correct, then it would be theoretically possible for gravitational effects to remain after the matter causing it is removed. This would be for a fraction of a second though, and would not explain any of the obsereved effects of dark matter. Gravity is just a bending of spacetime, it isn't an actual physical entity like the cupcake is.
>What if dark matter doesn't exist?
We need a different theory.
We _have_ different theories. I'm in favor of Steinhardt's ekpyrosis.
http://www.geocit...y01.html
These are often the same scientists who are adamantly opposed to an unseen entity involved in the operation of the universe, but unseen matter and unseen energy are OK with them.
At some point, science will doubtless devise theories based on the observed movement of masses without invoking magic particles.
http://www.presto...ndex.htm
Energy is not the emission of light, as anybody who has taken the first two months of a high school physics class can tell you. Energy does *cause* the emission of light from atoms, but that is not the sole action of energy.
There's nothing wrong whith making up a substance to fit known observations. We made up photons before we ever had proof that light had a particle nature. We made up atoms centuries before we had any expirimental proof that they existed. And early scientists made up the aether, which turned out to be false, but was their best explanation at the time.
All it takes to bend space is energy. Mass is not required (in fact all mass could just be a form of gravitationally trapped electromagnetic energy).
As for dark matter, there are countless possibilities. In fact quantum physics is obviously incomplete (although most physicists would like to think otherwise). It's biggest failures are the inability to predict particle masses (and obvious relations between them like Koide Formula for example) from first principles, *infinite* vacuum energy, Landau pole, the need for renormalization tricks, decoherence, etc.
There is no freaking way you can say anything meaningful about dark matter and dark energy without calculating vacuum energy! Infinite vacuum energy simple leads to infinite gravitation.
Without a proper theory of matter we can't say anything certain about the Universe as a whole, most of cosmology is just wild speculation.
Physics is in really bad shape. The biggest problem is that the real scientific problems the field faces are simply too hard for most of them so they came up with substitutions on which to work like string theory.
String theory is so popular because it can't be falsified, there are countless versions of it and the framework is so vast that everyone can find a niche for himself and keep churning out papers - the only measure of scientific ability these days. You can build your whole career on string theory and many do, you know you will get grants cause those grants are managed by other string theorists, you know you will publish cause peer reviewers are string theorists.
This whole deal is a terrible waste of money and talent.
Dark matter would accordingly be made up of stings of fundamental particles of thousands of different lengths down to a single fundamental particle. Even the largest of these dark matter string lengths, which also include just single fundamental particles, are much smaller than the smallest size they are proposing in the above article.
Another big problem I believe is that General Relativity is an incorrect model of gravity at stellar distances. First gravity is a pushing rather than a pulling force or warp in space, secondly gravity's dark matter currents are non-linear at stellar and galactic distances and move in a vortex manner when viewing its motions relative to a galaxy's stars.
Although this does not seem like the simplest model, it is one that can account not only for internal galactic stellar motions but also the motion of galaxies within a cluster as well as the Newtonian version of it within a galaxy's core and even the planetary motions of our solar system without resorting to an uneven distribution of dark matter in just the right places to account for a spiral galaxy's retention of form.
see pantheory.org for the whole theory.
I don't think there is a physicist alive who beleives quantum theory is complete. We all know that we don't know every thing there is to know. the reason why so many people research string theory is because they think that it actualy might be worth something if it ever gets worked out all the way.
No it isn't. Tell me one example where gravity pushes instead of pulls.
http://www.geocit...y01.html
Most physicians, I think, adhere to the Copenhagen Interpretation of QM, which means they are quite aware of its incompleteness.
No - this is a shortcoming which to overcome is only a question of time. When ether theory was formulated, it appeared to not be falsifiable at first, too, and it took several decades and the experimental ingenuity of michelson & morley to falsify the theory. And the genius of AE to build a revolutionary new theroy upon the ashes of ether theory.
The real attraction of string theory is its inherent beauty. You know, BigBang theory with its patchwork of dark matter, dark energy, inflation, and other magic entities has become old and lost the beauty of its infancy.
This is not a fair complaint because the same can be said of all the searching for a dark matter particle which is postulated by no theory.
It is the aspect that BigBang Theory fits very nicely into the world as the monotheistic religions see it. To leave BigBang Theory for good comes very gruesome for all those believers of "In The Beginning There Was ...". That's why they cling to it so desperately.
What a horridly ignorant statement. E=mc^2 is a relation of energy to mass and vice versa. Einstein wrote that equation along with special relativity, years before publishing his paper on general relativity, which is the one about gravity.
The Casimir force doesn't resemble a push even a little. A push requires a force behind each object being moved or two objects being pushed away from eachother. The Casimir force and gravity both have two objects pulling oneanother towards eachother. If gravity pushed, the sun, and therefore Earth, would never have been able to form.
Why would we leave big bang theory?
Two things:
1.The Casimir force has been observed by objects in a void. You seem to think that means the void is only between the two objects. It isn't.
2. Einstein said that all gravity is acceleration, not vice versa. If all acceleration were gravity, than any acceleration caused by magnetism would prove that gravity and magnatism are the exact same, which they most certainly, as far as modern physics has been able to work out, are not.
http://electrogra...ver.html
Sorry, but some physicists including most laymans have somewhat different idea about elegance of physical theory - and this was one of reasons, I started to deal with AWT.
Because several of the "alternative" cosmologies - especially the ekpyrotic theory which I'm in favor of - don't need an initial state of infinite density, infinite temperature and without any scientific explanation of its genesis.
The Big Bang Theory and the Ekpyrotic Theory are the exact sma ein all respects except one. The Big Bang claims that the universe was once a singularity, much like the ones theorized to be at the center of black holes, while the Ekpyrotic theory claims that the universe started out very cold and empty, but due to a collision of multidimesional branes, began an expansion of space, matter, energy and all the good stuff that we have observed today. I think both theories are interesting and neither should be thrown out. However, I personaly would tend to beleive the model with a singularity more than the model involving something outside our universe.
Since it is a single entity it is in immediate contact with itself over the whole volume it occupies. The initial inflation of the Universe could have been caused by such a single dark matter wave. Other matter precipitated out after inflation and are able to move through dark matter only interacting with it mass-energy: i.e. gravity.
Bohr should not have stated that particles and waves are "complementary" but should have asked the following questions: (i) Can a particle act like a wave (ANSWER NO!) (ii)Can a wave act like a particle (ANSWER YES!) A localised electron wave will have a centre-of mass and will move according to Ehrenfest's theorem like a particle; unless the boundary conditions change e.g. when it encounters a double slit!
But if the Copenhagen-group did not come up with a statistical Universe, uncertainty in position and momentum of a "point-electron", and complementarity, ALL THE HONOUR WOULD HAVE GONE TO SCHROEDINGER! DO I SMELL POLITICS OR NOT?
http://www.geocit...y01.html
I'm sorry, you're right. 'Void' is a purely conceptual state in which a region of space is completely empty. I should have said 'a region of space devoid of everything but virtual particles,' but I think 'void' sounds better. And thank you for clarifying on Casimir. That sounds much more reasonable now. However, I don't think you could apply the same concept on a cosmic scale.
Yes they can. You yourself recognize that electrons behave as particles most of the time, and as waves some of the time. All other particles also have a wave nature, it's one of the basic concepts of quantum physics.
Nope. You smell paranoia.
You are not following what I am saying: YES we all know that an electron can sometimes be modelled as a "particle" and sometimes as a "wave". What Bohr's complemenrtarity is saying is that when an electron is a particle it is really a particle with a point-charge, and when an electron is a wave it is really a wave. It is much simpler, and make more physical sense to realise that a wave changes when boundary conditions change, and that an electron can thus ALWAYS be a wave which seems to act like a particle when the boundary conditions are such that Ehrenfest's theorem can apply: i.e. when the wave becomes localised. The latter is physics, the principle of complementarity is "Alice in Wonderland".
Ooops! sorry, the Copenhagen interpretation does NOT believe in real waves! Nature supposedly consists of "mischievous particles" which statistically behave like a wave: Oh my!!! And which can even detect a magnetic vector potential when it does not exist!! Wow! Real 'virtual reality" is it not?
But ther electrons aren't actual waves. There wave nature come into play as a probability of the particle's location. The nodes improbabilities and the antinodes are highly probable. Besides, if all particles were actual waves all of the time, they would interfere constructively and destructively on a day to day basis. As I have never heard of two neutrons canceling eachother out, I don't really think the neutrons always act as waves.
http://superstrun...ndex.htm
http://aetherwave...ics.html
From this perspective, elementary particles are wave packet blobs, which are so dense, so that total reflection phenomena takes place and their wave bounces and undulates at place completelly.
You are thinking in terms of classical waves. Schroedinger waves are complex (imaginary numbers)entities since time is an imaginary dimension.
The probability interpretation is claptrap. The spatial intensity of the wave only give probalistic measurements when your measuring equipment allows it to resonate with different absorbers. By itself it is NOT a probability distribution. This is where the Copenhagen group succeeded to bamboozle both Einstein and Schroedinger as well as the theoretical physicits who ame after them. I still cannot believe that two of the most intellegent theoretical physicists we ever had, could have fallen for this red herring!
Alizee is on the right track, except for the "foam' concept. A "free electron" is a localised wave because space-time is curved around mass. The curved space-time causes the boundary conditions which localises a "free electron" so that its wave-ground-state is equal to its rest mass. After all there is no such thing as a "free electron". An electron far away from other material is bound within its own inertial refeence frame within which it is stationary: Both the position and momentum (which is zero) of its centre of mass is known simultaneously! This is also predicted by Ehrenfest's theorem!
Nested waves form the "density foam."
Particles are simplified models of the waves.
Particles are wave packets.
These statements can be debated?
I'm pretty sure time is not an imaginary dimension. If my understanding of time is lacking, please correct me.
So by your definition, what is a probability distribution and what real world examples are there of it?
Ok, I'm positive that spacetime will not curve around an electron so dramaticaly as to stop a wave of any sort. Basically what you are describing is the curvature around a singularity. spacetime is not a solid object for waves to be cut off by.
I agree with everything except the first statement. It should be, "everything has a wave nature." I have yet to see a convincing argument for a complete lack of particles.
x(1)=x, x(2)=y, x(3)=z and x(4)=-ict
What is i?
Any wave has to resonate with an apparatus to be observed. Thus when a diffracted wave approaches a screen with many absorbers, it will be absorbed by the one with which it resonates first. Many identical waves will thus be absorbed at different points which will give the wave intensity. This does not imply that the wave-intensity on its own is a probability distribution. The measuring apparatus determines the distribution of "collapse-points". If not it will mean that a photon from a far away star with an area of hundreds of kilometers will collapse all over the place instead of in your eye when it encounters your eye as the only measuring apparatus. This is patently absurd! Obviously there is a probability that it will not collapse in your eye, but this is totally determined by resonsnce (energy and time) not by actual uncertainties in the position and momentum of a particle!
OK I should have put it better: A "free electron" is stationary relative to its own inertial reference frame. For a wave to be a stationary, localised wave, it requires to be bound just as it has to be bound around a nucleus in order to be localised and stationary. Since its rest mass is inertia: i.e. resistance to being moved, it must find itself within a potential well which resists movement as soon as a force is applied. Such a well can be modelled as a virtual positive charge: Since this charge "appears" and increases in "free space" the potential well must relate to the structure of space-time.
Rather state it that everything is a field. There are no singular particles; only localised fields which can be accelerated like particles owing to Ehrenfest's theorem.
Ok, I'm stumped. I've seen the first three parts of that before. However, I have never seen x(4)=-ict. If you would be so kind as to tell me where that was derived, I would be very appreciative.
You make a good point, howewver, nobody beleives that the fact that light from a star may or may not reach your eye is soley dependent on the Heisenberg uncertainty principle. But if we know exactly where the light come from, exactly where you will be when the light comes near your position, and all the factors that could mess with the photon's path along the way, we would still be unable to determine whether or not the photon will hit your eye because of the uncertainty in velocity and position. What we can come up with is a series of where the photon might be, and that data is what makes up the probability wave. Uncertaintiy is not absurd at all.
You're still talking about a well in spacetime. What causes this well? The only thing I know of that could create a well in spacetime is a singularity. Since you claim the particles are waves, I will assume that these particles are not supposed to be singularities. What then causes spacetime to warp around the wave in question to the point where the wave is forced to stay localized? For that matter, how is that we can observe things that are inside spacetime wells? Any part of a well that would allow the electron wave to give off a photon would also allow the electron wave to escape and delocalize.
Any mass will create a "dent" or "well" in spacetime... As you know. It's not exclusive to singularities. It doesn't have to be a deep well, only slight negative or positive curvature of spacetime.
Sorry, a typing error: As Earls pointed out it should be x(4)=ict
It is here where we obviously differ. What Born's postulate says is that when you measure the positions of electrons represented by identical "waves" one will obtain a distribution of positions NO MATTER IN WHICH WAY WE MEASURE:
Thus if your eye is the only measuring apparatus in the Universe that the "photon-wave" encounters after it has left the star, then the measurements made by your eye on an ensemble of waves will, according to Born, give a distribution of collapses over an area of hundreds of square kilometers. Your eye is in Perth and the photon appears in Sydney.
Since, according to this thought experiment, the only apparatus that can make the wave collapse is your eye; then I believe that one must have that it will have to be in your eyse. It might not collapse when reaching your eye because at that time it is not resonating with your eye (Fermi's golden rule), but this does NOT mean that it collapses elsewhere because a measurement has been made.
Good arguments: How the well might be able to form I will come to below; but first: Experimentally we know that a "free electron" moving with a constant speed is in reality stationary within its own inertial reference frame. We also know that it moves as "a prticle": i.e. an entity with a centre of mass. We also know that when we want to move such an entity from rest within its own inertial reference frame it resists because mass also acts as inertia. How does mass do this? There must be an opposing force coming into action as soon as we apply a force in order to move it. This means that the "electron" finds itself within an harmonic potential well. One can model this well as being caused by an opposite charge situated over a perpendicular fourth space dimension. By then solving a harmonic wave equation one gets a localised wave with a ground-state energy which can be equated to the mass of an electron AND because this ground-state energy relates to an opposing force, it is clear why mass acts as inertia. Furthermore, for such an interaction over a fourth space dimension, there are no electric-field lines around a solitary electron in three-dimensional space: Thus no "infinite vacuum energy" does not come into play which has to be removed by the magic of renormalistion. When accelerating the electron it "pulls" its inertial opposite charge along, thus causing vibrations relative to this charge which generate an electro-magnetic wave within three-dimensional space. Within the "core" of the wave function time does not exist because the fourth dimension is a perpendicular space-dimension At a critical radius, of the wave space-time-curvature sets in. I have done calculations as far as I can go. The problem is to calculoate the interaction energy over the fourth space dimension (could it be dark-energy?): I believe that the answer must lie witin general relativity.
(ds%u03C3 e^(i %u03C3))^2 = (dx%u03C7 e^(i %u03C7))^2 (dy%u03C8 e(i %u03C8))^2 (dz%u03C9 e(i %u03C9))^2 c^2(dt%u03C4 e^(i (%u03C4 - %u03C0/2)))^2
%u03C7 = %u03C8 = %u03C4 = 0 and %u03C9 = %u03C0/4 then
ds^2 = dx^2 dy^2 i*dz^2 - c^2dt^2
http://www.geocit...y01.html
Why exactly must the electron be in an harmonic potetial well?
It seems presumptive to me to solve an equation for waves using the data of a particle to prove that the particle is actualy a wave. Was there a step that I missed?
No you did not miss a step! I was hoping you will raise these issues. The fact is that those wave equations (Schroedinger and Dirac) which incorporates the mass a priori cannot model a "free electron" because they already incorporate the ground-state energy which should emerge as a solution as an input.
There must thus be a wave equation which do not have mass as an input parameter but give it as the ground-state solution. Such a wave equation should interface with general relativity. The Schroedinger equation is a good approximation when calculating how an electron-wave will respond when the potential energy and boundary-conditions change; but I believe that it relates to a more general wave equation. Thus using it to calculate a free stationary electron is not correct since as pointed out by you: one is then "using the data of a particle to prove that the particle is actually a wave">
So what does mass and its associated inertia tells you? It tells you that when you apply a force to move a particle with mass, this force is resisted. Where does this force come from? It can only be a Hooke-type force. Such a force is the result of a potential well which can be approximated at its minimum by a parabolic-curve with a minimum. This is why I am postulating that every "free-electron" must be within such a potential well. The quantum mchanical "vibration" within such a well causes the mass-energy of an electron. This vibration is not caused by "a particle" with mass vibrating, but it is a localised Gaussian wave which we observe as a particle.
You say you are an undergraduate: I AM REALLY IMPRESSED BY YOUR SHARP LOGIC: Keep it up there is a great future ahead of you provided we can change the policies being applied by physics-journals. Einstein would not have been able to publish his seminal papers today. We must change this culture or else future Einsteins (and I believe you could be one) will NEVER again succeed to generate paradigm shifts in physics!
Every free-electron? That makes me wonder what a whole atom would look like.
That was almost poetic. Very well woven nonsense. Good job.
Well an atom is a superposition of matter waves: It is thus also a single wave-entity with mass and therefore I would think that it will thus also experience a restoring force causing inertia.
We need a more general wave equation which does not require mass as an input parameter and which is commensurate with general relativity.
Wouldn't that do weird things to the protons, though. Either the waves would reinforce eachother and make it look like one really big particle or they would cancel eachother out and there would be no particle. I would think that there would be an interaction between the potential wells and the particle/waves would never actualy meet.
Obviously when the electron and proton waves add, they form an entity: They will not add when they interfere destructively. This is why we have atoms. But at a low enough temperature such atoms can be formed by entanglement: This allows them to be diffracted as is experimentally observed.
Could that be done at room temperature? That could lead to some very exciting breakthroughs computer sciences, comunications, military developement, and energy technology.
Well either there would eventualy be a destructive interference or there would have to be some special force that keeps them from interating destructively.
(dsa e^(i*a))^2 = (dxb e^(i*b))^2 (dyc e(i*c))^2 (dzd e(i*d))^2 c^2(dtf e^(i*(f - pai/2)))^2
a = b = c = f = 0 and d = pai/4 then
ds^2 = dx^2 dy^2 i*dz^2 - c^2dt^2
http://www.geocit...y01.html
Yes I discovered this phase at toom temperature for electrons extracted by an anode from a cold "diamond-cathode"; and it persists to high enough temperatures so that the cathode and anode fails before the phase fails: i.e. the estimate is that this phase persists up to a temperature at which the cathode reaches 500 C. One cannot ascribe a temperature to the phase itself since it is not composed of individual entities which require a statistical distribution to model it. It is a single macro-wave.
It is easy to prove using Solid-State interface-models which have proved their worth in modelling electronic chips that in my experiment the voltage over the cathode and anode MUST become zero for thermodynamic equilibrium to manifest. Experimentally it is found that after thermodynamic equilibrium has been reached a current still flows around the circuit: This means that electrons are transferred from the cathode to the anode "through" the electron cloud between them without an electric field being present: This defines superconduction. It has NEVER been proved before that a current actually flows through a superconductor without an electric field driving it. In fact, the accepted models on superconduction cannot even explain how this would be possible within a superconductor! My experiment is thus the FIRST that gives incontrovertible proof that it actually does happen.
I have been trying for nearly 10 years to tell industry that I have superconduction at room temperature: They then ask the "experts" on superconduction to advise them. These experts then claim that what I claim is impossible because the accepted models on superconduction like the BCS model will become invalid if I am correct. They NEVER attack my physics though. Thus it is more mportant to the "physics-church" to protect accepted dogma than to argue physics!
What is even worse for them to contemplate, is that my experimental result proves that the Copenhagen interpretation of quantum mechanics has all along been wrong!
So they rather excommunicate me as if I have become a leper. Thank God one is not burnt at the stake anymore. Nonetheless the mental pain I have suffered is probably just as bad.
If you follow the flock you will be happily contributing NOTHING NEW. If you do not, you will find out in time that we are back to censorship of original thinking. Maybe it is because the journals are inundated with nonsense since the PC made it possible for everybody to slap together a paper in record time! Whatever the real cause, the babies are being thrown out with the bath water. Thanks for your good wishes. I wish you the same. If you want a peaceful life choose a physics-cult figure and lick up his backside until you dissappear so that you can fill his chair when he dies off! Good luck!
A. Unlit up dust, asteroids, brown dwarfs and black dwarfs.
B. Low energy neutrinos that increase the mass of the universe while still being invisible.
See the work of Dayton Miller.
http://www.orgone...ller.htm
I'm sorry, but I've read a lot of your posts. Are you claiming that you've created room temp Bose-Einstein condensate? If so the world would be giving you a medal, not slandering you. I'm in a rather heavy state of doubt.
Seeing as you've performed this and accomplished it, you should already have a patent for the process, meaning you're well protected telling us exactly how you've done it. So how exactly did you do it?