After a few provocative hints over the last few years, new results in the search for weakly-interacting dark matter have come up empty. The latest is from XENON100, a liquid-xenon scintillation detector under the mountain in Gran Sasso, Italy. Here are the talk slides by Elena Aprile (pdf) from the Dark Attack conference in Switzerland (via Flip Tanedo).
And here’s the money plot; dark matter mass is on the horizontal axis, interaction cross section between dark matter and nucleons is on the vertical axis. The colorful bands represent the exclusion limits; anything above that is ruled out.
A couple things to note. The blobs scattered around the plot represent those provocative hints I referred to — the tentative evidence from previous experiments that they might actually be seeing something. XENON seems inconsistent with all of them. However, you can only make a plot like this under certain theoretical assumptions. Even if those assumptions are quite likely to be true, it’s hard to be completely definitive about one experiment ruling out another one, unless they’re really using identical techniques (which none of these are). It’s possible, although maybe hard to imagine, that some complicated dark-matter physics can make everything consistent.
The second point is the dark grey area at the bottom right. That represents a bunch of theoretical predictions in supersymmetric models. As Flip cautions, we don’t have a sensible measure on the space of all models, so the blob should be taken as suggestive rather than definitive. But the suggestion is clear: we’ve ruled out some models, but there are plenty that we haven’t yet reached.
Progress continues. XENON100 used 150kg of liquid xenon; the plan is to upgrade to one ton. Once that happens, they should be able to improve the limits on the cross section by a factor of 1000, which will swipe into a much larger region of parameter space. We’ll see what happens.
LHC data rules out a m = 60-70 GeV SUSY WIMP and disfavors greatly a 130 GeV SUSY dark matter candidate.
The large scale structure of the universe rule out a m > 200 GeV WIMP and prefers a candidate in the KeV mass range which no SUSY theory that wouldn’t have been revealed at LHC already could accomodate.
Valdis Kletnieks @20: What is your source for PBHs requiring additional gravitational lensing events? At the 100,000 solar masses that Frampton et al expect, there would only be a million in the Milky Way, or one per 300,000 stars, which is far too few to result in any substantial number of discernable lensing events. My sources say MACHOs above 15 solar masses would not have been detected by any lensing studies so far.
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When researches do not understand what exactly they are searching for, they can find nothing. They do not understand the structure of the real space, they talk about: black halls, Big Bang, gravitational waves, weakly interacting particles, hot dark matter, could dark matter, Higgs boson, etc. BUT: any of these notions still never being determined correctly. They started from the theorem of everything. BUT: where is your description and determination of primary notions? Or, in other words, you shall start initially from the theorem of something. When primary things are determined, then the theory of everything can be presented in an easy way. And DARK MATTER becomes a conventional gravitational field that unified interacting objects. Field particles of this gravitational field are also field particles of the field of inertia, which takes its origin in quantum mechanics, or more exactly, in subquantum mechanics that describes direct interaction of moving material particles with the space. Who is interested in details, i.e. how dark matter appears from a submicroscopic theory of gravity, can read about it in this work entitled “Dark matter as seen from the physical point of view” Astrophysics and Space Science, vol. 335, No. 2, 619-627 (2011) http://inerton.kiev.ua/37_dark_matter.pdf
Dark matter,matter but dark. what does it means by meaning and also by nature.Every things in this univers has connection to other things,it is an universal thruth.so, dark matter has also connections with visible matter,energy and also with dark energy.
What are the possibllities?As I think:-
(1)we know Vsible matters are changable into visible energy.
Here,a question arises how visible matter created?Nothing else is available to convert into matter accept energy,as both are equivalent.Now,it is predictable that visible matter and visible energy are inter convertable.Hence,according to the law of conservation it is predictable that visible matter and energy are inversly proportional.such that,dark matter and dark energy are also convertable and equivalence to each other.But,
The question is where are they?
As, I explained before they must have any character towards matter and energy.What are those ?I think what is gravity and why it exists around masses,who helps light to travel into space?,why even light cannot escapes from black holes?
And,such many questions can be understandable and i have developed a theory on all these upper discriptions?And, according to my thinking darkness around us is the proof that dark matter is available around us because visible mass and energy is available.Gravity, space and time all belongs to the relation between visible matter and energy and dark matter and energy.
I know someone can declare me,mad.But,I have strong logics and concepts about upper words but not possible to write here due to large ness.And,I Want to discuss on it .so, i am waiting for replay.
Dark matter exists around matter.how?
According to newton’s law of gravity.Gravity depends upon four things m1,m2,distance between masses and gravitational constant.If we let that m2 with constant volume and distance is constant and m1 is extremly heavior and larger than m2 Now, between m1 and m2 with distance of ‘r’ there will be some gravitational force of attraction.
If volume of m1 decreases 100 times and distance is r than what will happen as mass of both objects are same?Definately due to increase in density, gravity will be increased.Now, if by normal codition volume of m1 is increased 100 times gravitational force must be decreased due to decrease in density.
Thus, it is predictable that gravity depends not only on mass and distance but also on density of matter.
It shows that space around matter is also related to gravity.space has also property of gravity.
Now,If space is related to gravity,it can’t be empty it is mustly made up of any particle which has property of gravity.
How it behaves towards matter for existance of gravity? Due to upper explanation an atom is not empty but it is filled by any particle which shows gravity?so, this particle exists with it’s on density.so,when matter exists it’s removes this particle according to it’s volume.Hence, the displacement of this particle make it more DENSER around the matter.I think this density is called TIME and is responsible for GRAVITY around matter.
That’s,why around black hole time is slower due to extreme high density and gravity also.
Question arises by which particle space is made up off.visible energy and and dark energy hasn’t property to show gravity.so,dark matter is the possible option.I think it is true because we can observe darkness in our daily life.Some one can say that where light is not available so the darkness exists.But,A person blind with birth don’t know or our body except eyes don’t know what is darkness?we can observe darkness only by our eyes.so, darkness exists.It’s visibility depends upon luminousity of light.I think it has property towards dark energy as well as visible matter and energy. It has different behaviour that’s why missing.
From an aesthtic point of view I think most scientists have lost track of the foundation for a new physics. At the first moment of the universe, what don’t we assume all coupling constants were equal to unity = 1.0000
Then things start to make sense, the new cosmology is an evolution something like Gravity: Electromagtetism was 1:1 and a process of graviton decay started the universe based on the linear decline of the fine structure constant so that eventually G/E = reverse exponential function of
1/1 as it ends up at currently 137.036. In another one hundred million years alpha ( fine structure constant will be 1/138 and the Gravitational force will not have changed enough to effect life processes other than DNA from the 1/137 to 1/138 All the big graviational change ( dG/dE )/dt would have occurred in the COBE era change