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Searching For Dark Matter From Deep Under an Italian Mountain

Zothecula writes "Like the Higgs Boson, dark matter is one of those things in the Universe that evidence points to, but is very difficult to pin down. A team of researchers is looking to verify the existence of this most elusive of ingredients that is thought to make up 23 percent of the Universe using powerful detectors buried deep in an Italian mountain. The DarkSide-50 project is an international collaboration between Italian, French, Polish, Ukrainian, Russian, and Chinese institutions, as well as 17 American universities. The project team spent last (Northern hemisphere) summer assembling the detector in a laboratory deep within the Gran Sasso mountain, which is accessed via an exit off a six-mile (9.6 km) long highway tunnel in Italy."

24 of 62 comments (clear)

  1. You will not hide from NSA by Anonymous Coward · · Score: 1

    So, they think by hiding under the mountain they can escape powerful USA regime?
    How naive.

  2. 23% by JeremyWH · · Score: 3, Funny

    Did they mention it makes up 23% of the universe?

    1. Re:23% by Sique · · Score: 1

      Yes, because it's a dark conspiracy!

      --
      .sig: Sique *sigh*
    2. Re:23% by dcollins117 · · Score: 1

      Did they mention it makes up 23% of the universe?

      Once or twice. Just in the summary though. Any more than that would just be showing off.

    3. Re:23% by Sockatume · · Score: 1

      23, 23, riding through the glen
      23, 23, with his band of men
      Feared by the bad,
      Loved by the free,
      23,
      23,
      23.

      --
      No kidding!!! What do you say at this point?
  3. Re:It's 23! by fyngyrz · · Score: 1

    What percent of the universe does dark matter make up???

    In the sewers of Rome... most of it.

    --
    I've fallen off your lawn, and I can't get up.
  4. Terrible summary by Anonymous Coward · · Score: 4, Informative

    To be clear, dark matter is nothing like the Higgs-Boson. The Higgs was predicted to be within a specific energy range and to decay along a specific subset of paths. The LHC was designed to reach or exceed the energy range of the Higgs and to detect its decay once it appeared. The Higgs appeared within the range predicted, decayed like predicted, and everything is fine and right with the world of predicted and accepted particle physics so far as everyone is concerned.

    Dark Matter on the other hand, is something which is not predicted by any theory we currently have. Its existence is only inferred by seemingly missing mass from galaxies and some astronimical observations that suggest this mass may be in the form of seemingly invisible matter that we have no currently confirmed way of detecting other than looking at the effect it seems to have on gravity. Heck we don't even know if it is matter to begin with, at least as we know it, but that' the closest thing we can infer other than it seems to be invisible and so the name "dark matter".

    Candidates of what dark matter is have been suggested. Or rather, quite vague candidates have. The most popular is the "WIMP" or "Weakly Interacting Massive Particle" that may or may not interact via the weak force at all, may have an energy/mass equivelance of who knows, and should for your guess is as good as mine not interact at all with the electromagnetic force or the strong force. Except we've built detectors, more and more of them with higher sensitivity and so far the only thing that's come back are what seems to be statistical errors.

    So, really they're pretty much the opposite. Dark Matter is largely a mystery who's properties are at best hoped to be like the physics we already know and understand, and the detector mentioned hopes that this hope is correct and that it will be. The other is a particle that was predicted decades ago, had an extremely solid theoretical understanding and backing, and who's detector was build largely with the expectation that it would turn up as predicted, which it did.

    1. Re:Terrible summary by Sockatume · · Score: 4, Informative

      I think you're being unfair to the submitter here; all they suggested was that the Higgs and dark matter alike have been difficult to tease out. That one's an issue of generating a large enough instrument to detect something we're very sure exists, and one's an issue of explaining the existence of something that we can see but not understand, is an excellent teaching point, and you've done a great job there.

      --
      No kidding!!! What do you say at this point?
    2. Re:Terrible summary by flyingfsck · · Score: 1

      Well, as the late great 'astronomer' Douglas Adams said: The missing matter is the plastic peanut packaging material that the universe came in.

      --
      Excuse me, but please get off my Pennisetum Clandestinum, eh!
    3. Re:Terrible summary by dissy · · Score: 1

      Dark Matter on the other hand, is something which is not predicted by any theory we currently have.

      Before you are at all taken seriously, you have a ton of explaining to do then.

      Since you claim General Relativity, Quantum Mechanics, and the laws of Thermodynamics are all not current theories we have, you must start by explaining what each one of those theories explains and then some

      You have to explain why the Sun exists, since it can't with the amount of gravity we actually see.

      You have to explain the cosmic microwave background image, and why it shows in multiple ways what you claim doesn't exist.
      Why does the image indicate 25% barionic matter and 75% non-barionic if that isn't actually the case?
      Why does the image show missing spectral lines for missing matter which you claim isn't missing because it doesn't exist?
      Why are solar systems the shape we see them in if gravity works the way you claim?
      Why are galaxies the shape we see them in if gravity works the way you claim?
      Why are galactic clusters the shape we see them in if gravity works the way you claim?
      How do you explain the galactic filaments since there isn't enough gravity for the universe to look the way it looks?

      Once you create a theory to answer all of those, you'll finally be caught up to "now" and can then proceed to wow us with the additional predictions your theory makes that turn out to be the case.

      Until then, the evidence is strongly against all of your claims.
      You and the people who modded you up should be ashamed.

  5. pinning down dark matter by ozduo4 · · Score: 1

    might end with a "Pop"

  6. Re:From the severed horsehead's mouth. by c0lo · · Score: 4, Funny

    Ah, Italia.
    The country were seismologists are thrown in jail because the can't asses the risks of earthquakes,ships run aground on calm seas and neutrinos run faster than light. If they can't find dark matter in the darkness under its mountains, noone can.

    On the other side, US is squeezing the last bit of the dark energy barrel (while it lasts)

    --
    Questions raise, answers kill. Raise questions to stay alive.
  7. Re:From the severed horsehead's mouth. by drinkypoo · · Score: 4, Informative

    The country were seismologists are thrown in jail because the can't asses the risks of earthquakes

    False. They were thrown in jail for their false claims.

    --
    "You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
  8. surprise by PopeRatzo · · Score: 1

    Maybe they'll find Jimmy Hoffa down there, too.

    --
    You are welcome on my lawn.
  9. Searching for WIMPs, not DM by mbone · · Score: 1

    To be accurate, the search in Gran Sasso is a search for WIMPs (Weakly Interacting Massive Particles), which are one microphysical explanation for dark matter. I personally do not like the common conflation of dark matter (for which there is abundant evidence) with WIMPs (for which there is no evidence at all).

    A lot of the interest in WIMPs comes from particle physics, due to the "WIMP miracle" (that hypothetical particles at the electro-weak scale, i.e., ~ 100 GeV, apparently have the right mass to explain dark matter) and the hypothesized connection between WIMPs and supersymmetry (i.e., that the WIMP could be a supersymmetric neutralino). After much experimental work, the WIMP miracle is almost dead experimentally, and the supposed connection to supersymmetry is not doing so well either.

    However (not that you would know from reading most articles on the subject), there are a number of other viable theories for dark matter. These include axions, primordial black holes (maybe), and macroscopic quark nuggets, which would have important practical implications should they be detected.

    1. Re:Searching for WIMPs, not DM by mbone · · Score: 1

      Er, \Lambda_CDM is the consensus cosmology these days, as it fits well with so much observational data, and predicted to an exquisite degree the anisotropies in the CMB as confirmed by everything from COBE & BOOMERANG to the latest WMAP data.

      True, but all that means is that any DM theory must be consistent with Lambda CDM (which is true for all the ones I mentioned, at least for a suitable choice of prameters). Note that there is still the "core-cusp" problem, which it now doesn't look like _Warm_ Dark Matter can solve, and thus remains a problem for all of these theoretical choices. (Macroscopic DM can act as WDM for suitable choices of mass and density.)

      CDM here is Cold Dark Matter, which of course need not just be WIMPs, but it was always a stretch to consider non-WIMP solutions, and MACHOs are effectively ruled out and axions have yet to appear in QCD experiments.

      MACHOs are not ruled out for masses less than that of the Moon (although there are interesting new limits for some lower masses from femtolensing - see
      here for a more fine grained description of mass spectrum constraints for dense macroscopic DM).

      As for axions, it seems strange to bring up that evidence for them has "yet to appear in QCD experiments," when of course evidence for WIMPs also
      has "yet to appear in QCD experiments." (There are of course also direct searches for both WIMPs, such as at Gran Sasso, and for axions, such as with the CERN helioscope, but in both cases these are also negative at present.)

      Although pretty much all \LCDM cosmologists are gauge theorists,

      Let's just say that, coming at this from an astronomical perspective, very few of the cosmologists I have known personally are particle physicists, and of course the Lambda part of Lambda CDM was forced upon us by astronomical observers. (I can, FWIW, remember going to cosmological talks in the 1980's where particle physicists confidently explained that the apparently large vacuum field energy in quantum field theories meant that the cosmological constant just had to be zero.)

      that does not mean that they necessarily ever supported SUSY; being general relativists as well makes it pretty easy to adapt to pretty much arbitrary mechanisms that generate the metric, and sky observations suggest what those mechanisms are likely to be, constrained by what is already proven in SM/BTSM physics.

      I don't think that anything has been experimentally proven in beyond standard model physics (except that neutrinos have mass).

      It's not that WIMPs came from particle physics, it's that literally they must not interact electromagnetically at all, they must not feel the strong nuclear force, they must be essentially collisionless, they must not clump significantly (distributions are gaslike and stay that way all the way down to where a "cusp" could be), they must be individually massive, and they must move mostly thermally, or there would be easily-observed sky artifacts.

      Limits on DM only limits on the Cross Section / Mass ratio. As Ariel Zhitnitsky is fond of pointing out, if the mass is small, the cross section has to be tiny, but if the mass is macroscopic, the cross section can be fairly large.

      Those restrictions sure seems like a good fit for some sort of heavy neutrino, and hey if SUSY's (well, say MSSM's) neutralinos might fit (they don't totally) why oppose searches for them in labs motivated by particle theories?

      I certainly do not oppose such searches.

      Especially if the searches narrow the particle space in which various other WIMP candidates might hide.

      However, in \LCDM there is nothing precluding a DM sector with arbitrary numbers of interacting fields; there could even be a whole "dark chemistry", with

  10. Re:From the severed horsehead's mouth. by foma84 · · Score: 1

    While I support your position, I won't mod you up, because you could have at least provided some detailed information and some links.

  11. eep by godxile · · Score: 1

    No thanks I'm not into BBW role play.

  12. These scientists... by Wormsign · · Score: 1

    They delve too greedily and too deep. Who knows what they will awaken... in the darkness...

  13. Re:From the severed horsehead's mouth. by 3.5+stripes · · Score: 1

    Most of what you said is correct, but italy is run by bankers on side, and the mafia, camorra and n'drangheta on the other, with politicians tell you to ignore the guys in dark suits behind the curtain.

    --


    He tried to kill me with a forklift!
  14. Re:From the severed horsehead's mouth. by 3.5+stripes · · Score: 1

    on one side, sorry

    --


    He tried to kill me with a forklift!
  15. Ether by DERoss · · Score: 1

    The more I read about dark matter and dark energy pervading the universe, the more I think about ether (also spelled "aether" or "æther"), which also was supposed to fill the universe. Dark matter and dark energy will never be found because they are as real as ether. See the Wikipedia article at http://en.wikipedia.org/wiki/A....

  16. Re:From the severed horsehead's mouth. by drinkypoo · · Score: 1

    While I support your position, I won't mod you up

    If you run around the block twice, you'll be my most athletic supporter.

    --
    "You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
  17. Re:Mussolini by mbone · · Score: 1

    Mussolini was on top of the massif, these detectors are deep inside the mountain (in a tunnel bored off of the 10-km A24 Autostrada tunnel underneath the mountain, which makes driving equipment in very convenient).