Shedding light on the existence of dark matter

Aug 08, 2012 by Andrea Retzky
Shedding light on the existence of dark matter
Elena Aprile

Some light has been shed on the search for dark matter.

A global team of scientists looking for evidence of the existence of dark matter announced that they found none from the leading candidates. The analysis of 13 months of data at the Gran Sasso National Laboratory (LGNS), a led by Elena Aprile, professor of at Columbia, provided no evidence for the existence of Weakly Interacting , the phenomenally-named WIMPs, that are the leading candidates for dark matter. This doesn’t mean that dark matter doesn’t exist, only that potential candidates can be ruled out.

The latest results draw from 225 days of gathering data, more than twice as much as was previously assessed in 2011. Such negative findings are an important step towards proving the existence of dark matter. By demonstrating what is not dark matter, researchers can further refine the realm of what might yet prove that dark matter does exist.

Cosmological observations consistently describe a universe where ordinary matter as we know it – people, the Earth, and planets – comprise only about 4 percent, with the rest being made up of new, as yet unobserved forms of so-called dark matter and dark energy. The Standard Model of physics, the theory that explains how all matter interacts with each other, also suggests that dark matter exists. It is thought that dark matter is made of clouds of exotic subatomic particles left by the Big Bang, the aforementioned WIMPS.

“We’ve mastered one the most promising technologies for making the next step in sensitivity required to see if dark matter is indeed made of new particles,” said Aprile. “It is hard for anyone to intuitively grasp that we live in a universe dominated by stuff which we cannot see—but how can anyone resist finding out what this stuff is which permeates us all? Whatever it is, we know it's out there in huge amounts. It can be hiding in places we are not even looking, but this only means that we must continue to search to test all possible scenarios until we find the truth.”

Aprile’s experiment utilizes an ultra-sensitive device, the XENON100, which measures tiny charge and light signals expected from rare collisions between WIMPs and the nuclei of xenon atoms. The detector, which was built at Columbia, consists of a stainless steel container filled with ultra-pure liquid xenon –one of the heaviest elements, three times the density of water – sandwiched between two highly sensitive cameras. It is located beneath 5,000 feet of rock at LGNS, part of Italy’s National Institute of Nuclear Physics facility some 80 miles from Rome, in a chamber of lead and copper to help filter out cosmic and background radiation that may otherwise be mistaken for WIMPS.

“As an experimentalist, I could not be more proud of the amazing performance of the XENON dark matter project,” said Aprile. “The new XENON100 results show that this detector is the most sensitive for the direct observation of particle dark matter. The absence of a signal in the larger data sample means even more rare interaction rates of the dark matter with normal matter. This makes the search more challenging and at the same time widens the gap between XENON and the other direct searches. It feels lonely but at the same time exciting to be at the forefront of this search.”

Aprile will continue to lead experiments with XENON100, as well as XENON1T, now under construction, which will be a larger, more massive, and even quieter detector than XENON100. In Aprile’s describes it, whereas the XENON100 is about the size of a room, the XENON1T will be the size of a house. The new experiment should either find evidence for or push scientists to consider other forms of .

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User comments : 16

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IronhorseA
3 / 5 (4) Aug 08, 2012
Or perhaps its time to investigate General Relativity's inherent nonlinearity further to see if it is sufficient to explain the dark matter 'effect' without resort to unseen mass.
Satene
1.4 / 5 (14) Aug 08, 2012
Negative result is a result too. If only the physicists would be so tenacious at the case of really useful research, like the cold fusion. At any case, such a result renders the supersymmetry theory even more problematic and of course all theories which depend on it (superstring theories, MSSM extension of Standard Model) as well. Note that the latest finding of Higg boson-like particle disfavours the supersymmetry too because of its because of its relatively large rest mass.
Satene
1 / 5 (7) Aug 08, 2012
The new experiment should either find evidence for WIMPs or push scientists to consider other forms of dark matter.
Weren't we told so already when the former XENON 10 project was supposed to be replaced with XENON 100 in 2007?
Anda
1.4 / 5 (10) Aug 08, 2012
Fucking article. "Found nothing, that means there is something",
Normal matter: "people, earth and planets".

I've stop reading it. Who writes this bullshit? What's the meaning? To have a lot of dumb comments? To make stupid people think that's science so they can reply with dumb theories?
You got it.
Satene
1.7 / 5 (11) Aug 08, 2012
If you would censor the informations about negative results, then the informational bias will pervade the science gradually. IMO what the mainstream physics is missing are unambiguous criterion of falsification of its theories. Recently I read, that LIGO didn't find gravitational waves. Even with using of squeezed light detectors, entaglement and with all improvements, which were announced as a ultimate way for gravitational wave detection, they found nothing again. It's evident, LIGO is already sensitive enough, but the physicists involved don't want to lose their dreams and jobs. But at the moment, when some finding (like the cold fusion) could threat the jobs in existing research, the physicists are all very quick in dismissal of finding as a single man. We still have no tools, how to handle such a cognitive bias.
TimESimmons
1 / 5 (10) Aug 08, 2012
still no dark matter.... here's why:-
http://www.presto...ndex.htm
Satene
1 / 5 (9) Aug 08, 2012
still no dark matter.... here's why:
You're actually implying the existence of dark matter, not refusing it. IMO the dark matter is mostly formed just with vacuum fluctuations of slightly negative curvature - only subtle portion of it condenses into neutrinos, which could be understood as the lightweight supersymmetric particles (photinos) and antimatter at the same moment. But the existence of heavier particles in the sense of SUSY predictions is doubtful. Heavier antimatter particles indeed do exist, but they're not "weakly interacting" - they're forming positrons and antiprotons with charges. The same situation exists with gravitational waves - they physicists cannot detect them, while ignoring the existence of CMBR noise. Their theories aren't completely wrong, but they're leading to confusing predictions. So that the failure of physics has two sides: not only physicists didn't find, what they expected, but they even missed well known artifacts during this.
dschlink
4.6 / 5 (11) Aug 08, 2012
Science is very much about eliminating possibilities, AKA negative results. Finding the Higgs took years of narrowing the possible energy range. Various calculations gave multiple mass ranges. Each one in turn was eliminated until only one range was left and there is was!
vacuum-mechanics
1 / 5 (6) Aug 09, 2012
Weve mastered one the most promising technologies for making the next step in sensitivity required to see if dark matter is indeed made of new particles, said Aprile. It is hard for anyone to intuitively grasp that we live in a universe dominated by stuff which we cannot seebut how can anyone resist finding out what this stuff is which permeates us all?

May be it is no need to use such a high technology to find dark energy/matter. What we have to do is to change our concept of empty vacuum space to physical medium which exists as infrastructure of our space-time, then we would found that actually the mysterious dark energy/matter is in front of our face as explained below.
http://www.vacuum...id=14=en
Eoprime
3 / 5 (2) Aug 09, 2012
IMO the dark matter is mostly formed just with vacuum fluctuations of slightly negative curvature ...

-Mr. Waterripple Zeph (Satene/natello/Sanita/Bewia..ect.)

Now you are confusing me, in my opinion your opinion was that DM is the shielding from shielding from shielding of Waterripples? Do you want to infer vaccuum fluctuations are GW's? I smell BS... (as always when i read your gibberish)
LordKinyambiss
1 / 5 (1) Aug 09, 2012
The Standard Model has really been the most effective all-summing Theory of the Universe. Predictions tend to quite often come true. However I struggle not to wonder if DM and DE might actually be some other exotic manifestation of unknown physics. If XENON1T fails to find these lil' WIMPS, will focus shift to SUSY and other potential candidates?
Satene
1 / 5 (5) Aug 10, 2012
As I wrote already in the above post, the existence of WIMPS is predicted just with SUSY, so SUSY isn't potential candidate here. The focus will definitely shift to something very similar, because physicists want to keep their jobs and they're difficult to requalify to another branch of physics.
stuver
5 / 5 (3) Aug 10, 2012
Satene:
... Even with using of squeezed light detectors, entaglement and with all improvements, which were announced as a ultimate way for gravitational wave detection, they found nothing again. It's evident, LIGO is already sensitive enough, but the physicists involved don't want to lose their dreams and jobs. But at the moment, when some finding (like the cold fusion) could threat the jobs in existing research, the physicists are all very quick in dismissal of finding as a single man. We still have no tools, how to handle such a cognitive bias.


As the author of the LIGO link this quotes, I want to point out that the author has misstated the sensitivity of LIGO. LIGO has not detected a gravitational wave yet - TRUE. But we have been offline for upgrades. These upgrades have not been completed and no search at the sensitivity implied here has happened yet. E.g. squeezed light application to LIGO has just been proven very possible but not yet applied.
julianpenrod
1 / 5 (4) Aug 11, 2012
As Satene mentioned, in the case of things like cold fusion, the attitude of "seince" is, if they don't get results the first time, declare the idea completely discredited and never broach it again. Doesn't it just sound so much like that pithy phrase that "insanity is doing the same thing again if it didn't pan out the first time and expecting a different result". Where are the "scientists and other such aphorism spouting know-it-alls when Washington responds to economic sanctions not working by piling on more economic sanctions? The fact is, there is a fatal flaw in all this and that is leaving reportage on the situation solely in the hands of those with a conflict of interest vested interest in keeping the "research" going. Until and unless provisions are made for "rank and file" to get their hands on actual, persoinally corroboratable proof, nothing "science" says must be taken at face value. At least until it's ascertained that no "scientists" are craven operators.
Ensign_nemo
5 / 5 (1) Aug 12, 2012
This reminds me of the Michelson-Morley experiment to find the effects of ether on the propagation of light as the Earth revolves around the Sun.

Negative results can kill bad theories and open up an ecological niche for better theories.
ValeriaT
1 / 5 (7) Aug 12, 2012
Negative results can kill bad theories and open up an ecological niche for better theories.
This is just another bad theory. For example, the string theory was refused with experiments many times, but because there is lotta job positions behind it, these results are simply ignored under hope, some other results will bring the change. When the theory or phenomena is perceived as unconfortable, then its refusal is a matter of few years (cold fusion, aether model, etc.)

Unfortunately, there is no objective criterion of validity of experiments at the moment, when their result is subject of some interpretation. This interpretation may be wrong as well. The negative result of M-M experiment does imply the non-existence of aether only at the case, when longitudinal waves are considered. But as we know, the light waves are transverse waves. Did somebody considered this option? Nope, but the aether model was still dismissed.