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Science

Scientists Restart Large Hadron Collider in Quest for Dark Matter (cnn.com) 80

Deep underneath the Alps, on the Swiss-French border, something significant just happened in the world of physics. The Large Hadron Collider, Earth's most powerful particle accelerator, was restarted on Friday morning after a three-year hiatus for upgrades. From a report: Consisting of a ring 27 kilometers (16.7 miles) in circumference, the machine is made of superconducting magnets chilled to 271.3C (-456 F) -- which is colder than outer space. It works by smashing tiny particles together to allow scientists to observe them, and to see what's inside. It may sound like the stuff of science fiction, but the revamped collider will ultimately allow mankind to observe dark matter, physicists hope. Back in 2011 the Large Hadron Collider, located 100 meters underground at the European Organization for Nuclear Research (CERN), helped scientists prove the existence of an subatomic particle called the Higgs boson -- which is thought to be a fundamental building block of the universe dating back to the Big Bang billions of years ago.

CERN said on its website that the collider magnets "squeeze" tiny particles causing them to crash together, which scientists then observe. These particles are so tiny, CERN said, that lining them up to smash together is "akin to firing two needles 10 kilometers apart with such precision that they meet halfway." Improvements to the collider mean scientists will be able to study the Higgs boson in "great detail," CERN said in a press release Friday. Now a team of experts hope to be able to collide yet more particles together with the aim of understanding the mysteries of dark matter -- an invisible and elusive mass that can't be seen because it doesn't absorb, reflect or emit any light.

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Scientists Restart Large Hadron Collider in Quest for Dark Matter

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  • I for one am happy to hear they'll once again be crashing huge male members into each other. Ever since the great PornHub purge, there's been a need for fresh, uh, content.

    ..oh, that said Hadron Collider? Oops.

  • by fermion ( 181285 ) on Friday April 22, 2022 @05:08PM (#62470092) Homepage Journal
    https://www.youtube.com/watch?... [youtube.com] Of course the Higgs has been verified but some va;yes do not match the standard model. So the LHC is pointing us to new physics in the future. I think as we discover if so called dark matter is real or just a kludge will be critical in the future direction of physics.
    • Higgs has been verified but some va;yes do not match the standard model.

      No, the depressing thing is that the so far the Higgs' properties exactly match the SM to within their measurement accuracy. Hopefully, this new run might get enough statistics to start seeing some difference but so far it's the Standard Model all the way down.

      • by fermion ( 181285 )
        Some values meaning things like the W boson. The Higgs is exactly as expected.
        • No it i snot as expected, it is to light.

        • Some values meaning things like the W boson.

          Let's see if that stands the test of time first. The W mass measurement is incredibly hard to do because you have incomplete information to reconstruct it due to the neutrino - or alternatively huge backgrounds at a hadron collider if you go for the quark decays. This is not the first (or even second!) time CDF has reported a significant anomaly although it probably is the largest significance e.g. the di-jet excess from ~2011. It may be something or it may well turn out not to be.

      • > but so far it's the Standard Model all the way down.

        That's disingenuous. There are numerous problems [wikipedia.org] with the Standard Model.

        • While there are, as you say, definitely problems, I think it is fair to say, "so far there are few-to-no new results that would seriously constrain model building or point towards the model we should be building." Within the context of somehow expanding the SM, we require either a new coupling between existing particles, or a new field(s) with new couplings. Unfortunately, so far all results are doing is just ruling every proposed useful extension (e.g. not string theory) out.

          And unfortunately, as is the
        • That's disingenuous. There are numerous problems with the Standard Model.

          It's not at all disingenuous. There are indeed problems with the SM and we know that there must be physics beyond the Standard Model somewhere - I've been looking for it myself for the past 20+ years with no luck. So, as I said so far it is the Standard Model all the way down. At some point, we may - or even should - hit turtles but we have not done so yet.

      • No idea why you pollute /. with your fake knowledge: https://home.cern/science/phys... [home.cern]
        We do not even know if the discovered particle is the Higgs boson.

        For people interested: the discovery at CERN is a candidate to be the Higgs boson, and it is a magnitude lighter than the SM (standard model) predicted.

        • No idea why you pollute /. with your fake knowledge

          I've no idea why you can't read the link you posted. Nothing in it contradicts what I wrote. We know that the particle we found has spin 0 and positive parity ith over 95% confidence. We also know that it couples to photons, W and Z bosons plus taus and b-quarks since it decays to them with branching ratios exactly consistent with the SM predictions within the accuracy of the measurements. So far it is precisely consistent with being the SM Higgs boson.

          If it walks like a duck, quacks like a duck and lay

          • And we know it is an order of magnitude, probably 2, to light.

            • The Higgs boson is (by some measure at least) actually about 14 orders of magnitude too light. This is known as the fine-tuning problem because the mass of a fundamental scalar will naturally get dragged up to the Planck scale because it has "corrections" to it that are of the order of the energy scale squared. So effectively, to get a mass of ~100 GeV you need a series of "random" numbers each of order 10^38 to add together to give a sum of order 10^4. There has to be some physics to explain such an amazin
  • I would like to know what physicists hope to learn from collisions that would apply to dark matter. As far as I know, the only evidence we have for dark matter is gravity.
    • by burtosis ( 1124179 ) on Friday April 22, 2022 @05:21PM (#62470138)

      I would like to know what physicists hope to learn from collisions that would apply to dark matter. As far as I know, the only evidence we have for dark matter is gravity.

      I would like to know what physicists hope to learn from collisions that would apply to dark matter. As far as I know, the only evidence we have for dark matter is gravity.

      The very short answer is the collisions have so much energy in such small spaces you can create pretty much every kind of particle with that or less energy with enough collisions. Measuring at a new higher level shows more of what can happen, and perhaps if we keep careful tabs on missing energy reveal missing particles that weren’t detected.

    • by backslashdot ( 95548 ) on Friday April 22, 2022 @05:21PM (#62470142)

      Yes, so far the only evidence we have is gravity anomalies. While there's theories of axions, WIMPS, sterile neutrinos, geons etc. the biggest reason is that colliding things have proven very enlightening for science in the past. It is also super fun, so why not?

    • by fermion ( 181285 ) on Friday April 22, 2022 @05:26PM (#62470156) Homepage Journal
      Symmetry. It is what a bunch of physics is based on. When it is broken, there may be something fishy going on. It is what lead Einstein to his theories. It is why we look for a magnetic particle, because all other maxwells equations have a non zero gradient. If there is a break in symmetry in the collisions it could be an indication of dark matter.
    • They hope to find hypothetical force-carrying particles called leptoquarks and Z primes which could be evidence of a fifth force. Most physicists believe that dark matter consists of new, undiscovered subatomic particles, but some believe that it could be related to an unknown fundamental force.
    • by Baloroth ( 2370816 ) on Friday April 22, 2022 @06:26PM (#62470390)

      So, the way particle colliders work is by smashing together particles at very high energy. This energy allows the production of new particles, particles that are very massive and unstable, and which decay very very rapidly. Because these particles are unstable (and only produced at very high energies), they don't exist freely in the universe today (except in exotic locations, like supernova or near black holes). However, they did exist in large quantities in the early universe, when the entire universe had energies at (or higher) than that found in colliders.

      Nearly all dark matter theories include some form of production mechanism that couples dark matter to more normal matter*. This allows some interaction between normal matter and dark matter (allowing for direct detection experiments to search for dark matter directly), and indirect astrophysical searches to look for signs of dark matter interacting with itself or other matter. The coupling between most everyday matter and dark matter is very small (or we would have found dark matter already), but it might be significant with the matter produced in particle colliders (because these particles have higher mass and energy, and so can decay and interact in ways everyday matter on earth cannot). So, the hope is, by producing lots of these particles, and looking at the results, we can see if we're producing dark matter, or at the very least eliminate some theories about how dark matter is produced. This is hard, of course, since you can't directly detect any dark matter produced (since all of the detectors are made of normal, low-energy matter with aforementioned weak coupling), but it's possible to look for what we're not seeing (missing energy searches), or we may see things we don't expect (indicating new processes) that can only be explained by dark matter production in the detector.

      *This production mechanism is important to explain how dark matter came to be in the first place: it's theoretically possible dark matter and normal matter co-exist completely separately (only interacting through gravity), which is philosophically unsatisfying, but more importantly this production can explain the amount of dark matter in the universe. If dark matter was completely separate from normal matter, there wouldn't be any reason for the amount of dark matter to be anywhere close to the amount of normal matter. But they are fairly close: there's more dark matter, but only by a factor of 6 or so. If the dark and normal matter were unrelated, the quantities of both would be random, and they could easily be different by a factor of a trillion, or 10^1000, or anything. This would be a fine-tuning problem, and physicists like to avoid them (they're usually a sign of something we don't quite understand yet, rather than an actual thing). Instead, introducing a coupling allows for a natural production of specific ratios of dark matter to normal matter in the early universe. There are dozens of theoretical mechanisms for this (freeze-out, freeze-in, non-equilibrium decay, coherent field oscillations, etc.), and collider searches can help eliminate or constrain some of them.

      • by znrt ( 2424692 )

        there's more dark matter, but only by a factor of 6 or so. If the dark and normal matter were unrelated, the quantities of both would be random, and they could easily be different by a factor of a trillion, or 10^1000, or anything

        sorry, what?

        they could easily be different by a factor of a trillion as they could easily be exactly the same, or a factor of 6. yeah, random. what's that supposed to prove?

        • sorry, what?

          they could easily be different by a factor of a trillion as they could easily be exactly the same, or a factor of 6. yeah, random. what's that supposed to prove?

          Because it indicates that the ratio probably isn't random. If it was random, there is no reason it would be reasonably close. It is reasonably close, so there is likely some physical process that causes them to be connected. Anytime in physics our universe requires a physical parameter to take on a particular value (or a relatively small range of possible values, and compared to the set of all positive real numbers, 1 to 10 is infinitely small), it suggests that this value is not a result of random processe

          • by znrt ( 2424692 )

            thanks for the explanation but this still sounds like an extremely weak assumption to me.

    • I would like to know what physicists hope to learn from collisions that would apply to dark matter.

      The reasoning is actually quite simple. Whatever Dark Matter is it must have been created by particle collisions in the Big Bang. Depending on your preferred model of Dark Matter the reason we have not yet seen it when colliding particles is that we have not yet collided them with enough energy to produce it. Hence, you can look for it by smashing particles together at higher and higher energies hoping that at some point you'll cross the energy threshold to produce it.

      Unfortunately, the main reason why

  • These particles are so tiny, CERN said, that lining them up to smash together is "akin to firing two needles 10 kilometers apart with such precision that they meet halfway."

    So we can find out what happens when you cross the streams? I‘m a bit fuzzy on it exactly, but something tells me bad things would happen.

  • by Anonymouse Cowtard ( 6211666 ) on Friday April 22, 2022 @05:18PM (#62470130) Homepage
    TFA makes no mention of the search for a fifth force [theguardian.com], which is something else to get excited about with the newly whiz banged LHC.

    Not sure what I'm more keen for more news on - the LHC or the JWST. Either way, or both, the coming months will be huge, perhaps revolutionary, for science across many disciplines.

    • Re: (Score:3, Interesting)

      by fermion ( 181285 )
      While lesser sciences such as biology enjoys zoos, physics does not tolerate them. The [article zoo was tamed by quarks. There was the electro force and the magnetic force. All school kids know these are just perpendicular comments of the same force. Likewise the weak and strong nuclear force are likely consolidated as well.

      The only force not consulates under QM is gravity. So we have at most two forces. This falls into line that QM and relativity cannot be normalized at this point. The fifth force could

    • ...which is something else to get excited about with the newly whiz banged LHC.

      Only if you do not understand statistics. While it's true that the chance of the result happening by chance is about 1 in 1000 when you have produced over 1,000 measurements this sort of thing is expected. That's not to say that it may not turn out to be something but I've seen plenty of 3-sigma results disappear with more data. ATLAS and CMS had one a few years ago with a ~780(?) GeV/c^2 mass-bump at jut under 3-sigma remarkably seen in both experiments which disappeared with more data.

      • No need to be a smarmy prick. The CDF teamâ(TM)s new measurement of the W mass are sigma-7 and not by chance.
        • No need to be a smarmy prick.

          I'm not - I'm pointing out statistical reality to deflate the media hype. Sorry if you prefer the hype but reality is somewhat different. LHCb and its predecessors Babar and Belle have on multiple occasions come up with 3+ sigma deviations from the SM and literally none of them have turned into anything. That's not to say that this one will not be something but given their past record, this is not yet a result to get excited about.

          As for the CDF result, it's similar. The W-mass measurement is one that i

        • by ceoyoyo ( 59147 )

          It's not a new measurement, and while it's six and a bit sigma away from the standard model predictions, you can't ignore existing evidence.

          The CDF result is a new *analysis* of old data. It disagrees quite a bit with both the original analysis of the same data, and everyone else's data. When you put everything together you get about a three sigma disagreement with the standard model, which is interesting, but a long way away from definitive.

  • Scientists Restart Large Hadron Collider in Quest for Dark Matter

    Can they do that with just large hadrons or will they need small and medium ones too?

  • CERN said on its website that the collider magnets "squeeze" tiny particles causing them to crash together, which scientists then observe.

    No, CNN. The magnets confine and accelerate the particles, so that two particle beams can have a head-on collision.

    • Bad science reporting was visible from the first words of the article: "Deep underneath the Alps, ...".
      Well, the LHC is certainly not underneath the Alps, it is under a plain near lake of Geneva. The nearest mountains to CERN are called the Jura. The nearest particle lab underneath the Alps is ~100 km away under the Mont-Blanc.

  • ...the Republican party & QAnon that they're doing this & that it might create a black hole that'll suck the earth into it? I really, really wanna see them do that again. Please, pretty please?
    • You're confused, Republicans were huge supporters of collider programs. USA would have had the most energetic collider on Earth, 3 times that of LHC, but Democrats cancelled it.

      • It's congressional support shrank as the list of possible sites shrank. Everyone wanted a collider - in their own state.

      • by gtall ( 79522 )

        The key word here is "were". Now, Republicans view science as anathema to all they claim to stand for.

        • Wrong, reality doesn't match your made up fiction. In 2018 was the largest research spending increase in a decade.

          https://www.science.org/conten... [science.org]

          • by gtall ( 79522 )

            Gobal Warming? Republicans out to lunch. Care for the environment? Republicans out to lunch. Evolution? Republicans out to lunch. And their spending increase didn't make up for all the cuts they've inflicted on research over the years.

            They also cut funding research on viruses carried out in other countries where they have them before they get here. According to Pew Research:

            "Around six-in-ten Democrats and Democratic-leaning independents (62%) favor this now, up from 46% in 2013. Four-in-ten Republicans and

            • You're hilarious.

              Global warming? Biden begging Venuzuela and Saudi Arabia to pump more, he promised the moon for energy and has delivered essentially squat.

              Viruses in other countries before they get here? You're spewing nonsense, since that was in 2020 when the Coronavirus had already arrived here. Proof that money was being wasted with no benefit whatsoever.

              Evolution? How is that a voter issue, voters largely don't give a shit, evolution happens with or without my tax dollars. Irrelevant, even if it'

      • "opening the gates of hell" seems to be one of the looney right's many favourite slogans. The LHC is the key to unlock them!
  • by kbahey ( 102895 ) on Friday April 22, 2022 @06:08PM (#62470340) Homepage

    The upgraded collider could reveal a fifth force [bbc.com], or even dark matter [bbc.com]

    • by quenda ( 644621 )

      The upgraded collider could reveal a fifth force [bbc.com],

      "Fifth" force? How about a fourth? It has been 100 years now since Einstein showed gravity is not a "real" force, and it is time to Pluto it.

      We could call gravity what? An apparent force? An emergent force? Given how small it is compared to the others, "Dwarf Force" would be my preferred option.

      • by Kremmy ( 793693 )
        Gravity is the only thing keeping our magnetosphere going which in turn is the only thing keeping the life ending rays from penetrating our atmosphere. It's this big ball of mass that we have orbiting us (gravity) and swishes the water across the whole surface as it does. That force is churning the core of our planet to create that magnetosphere.
        It's so insignificant that it's the only thing keeping us alive.
        • There is no gravity, only collapsing time-space. What you mistakenly think gravity is, is really the amount of acceleration it takes to remain stationary in a collapsing time-space field.

      • by ceoyoyo ( 59147 )

        It's unfortunate that turned into a sound bite everyone remembers.

        General relativity is a geometric theory of gravity, sure, but you can write down electromagnetism the same way. We don't usually because the quantum field theory version has some really nice properties. So nice that we'd really, really like an equivalent for gravity.

        To save the silly arguing, "force" is generalized to "interaction." We're actually looking for the sixth force/interaction, because the Higgs interaction is the fifth.

      • Look up Verlindesâ(TM) Theory about Entropic Gravity

    • Would it have revealed more of Milla Jovovich?

  • Have they given up on them? For, without them viable string theories necessitate an even more preposterous number of spatial dimensions, I believe.
  • Chilled to "271.3C". So cold that I can feel my skin vaporising and my blood evaporating.

  • Every attempt to find or identify what is causing the gravitational effects that are imputed to "dark matter" has failed. It seems likely that the problem is with theory. Sure, a few billion more to show what it isn't seems fine; particle physicists need to pay mortgages, too.

  • https://home.web.cern.ch/news/news/accelerators/large-hadron-collider-restarts
  • the machine is made of superconducting magnets chilled to 271.3C

    I would argue that 271.3C is actually quite warm. Either that or the Slashdot editors can't even copy-paste competently.

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