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ATLAS Results: One Higgs Or Two?

TaeKwonDood writes with news from CERN about more results in the search for the Higgs Boson, this time from the ATLAS experiment. Researchers report peaks in the data in accordance with what they'd expect from the Higgs. The curiosity is that the peaks are a couple GeV away from each other. "The ATLAS analyses in these channels return the best fit Higgs masses that differ by more than 3 GeV: 123.5 GeV for ZZ and 126.6 GeV for gamma-gamma, which is much more than the estimated resolution of about 1 GeV. The tension between these 2 results is estimated to be 2.7sigma. Apparently, ATLAS used this last month to search for the systematic errors that might be responsible for the discrepancy but, having found nothing, they decided to go public." Scientific American has a more layman-friendly explanation available. As this work undergoes review, physicists hope more eyes and more data will shed some light on this incongruity. Tommaso Dorigo, a particle physicist working at the CMS experiment at CERN, writes, "Another idea is that the gamma-gamma signal contains some unexpected background which somehow shifts the best-fit mass to higher values, also contributing to the anomalously high signal rate. However, this also does not hold much water — if you look at the various mass histograms produced by ATLAS (there is a bunch here) you do not see anything striking as suspicious in the background distributions. Then there is the possibility of a statistical fluctuation. I think this is the most likely explanation." Matt Strassler provides a broader update to the work proceeding on nailing down the Higgs boson.

30 of 73 comments (clear)

  1. One Higgs, Two Properties by Sponge+Bath · · Score: 5, Funny

    One is the Happy Higgs, the other an Angry Higgs. Being angry adds 3GeV.

    1. Re:One Higgs, Two Properties by Chemisor · · Score: 5, Funny

      Now, now, we don't have "angry" in physics. The offical term for that condition is "excited".

    2. Re:One Higgs, Two Properties by steelfood · · Score: 2

      Dopey Higgs takes away 3 GeV, Sleepy Higgs is another 3. Meanwhile they can't seem to find Bashful Higgs.

      --
      "If a nation expects to be ignorant and free in a state of civilization, it expects what never was and never will be."
    3. Re:One Higgs, Two Properties by maxwell+demon · · Score: 2

      One is the Happy Higgs, the other an Angry Higgs. Being angry adds 3GeV.

      Anger leads to the dark side...

      So, the god particle and the devil particle?

      --
      The Tao of math: The numbers you can count are not the real numbers.
    4. Re:One Higgs, Two Properties by maxwell+demon · · Score: 2

      Actually, the two particles are Susy Higgs Enterprise and OPENSusy.

      --
      The Tao of math: The numbers you can count are not the real numbers.
  2. Had to Be Done by organgtool · · Score: 5, Funny

    Apparently, ATLAS used this last month to search for the systematic errors that might be responsible for the discrepancy but, having found nothing, they decided to go public.

    It looks like ATLAS...
    puts on sunglasses
    shrugged
    YEEEEAAAAHHH!!!!!!

  3. Obesity by Hardhead_7 · · Score: 3, Funny

    After they started weighing the Higgs, it went on a diet.

  4. "God's particle" by Anonymous Coward · · Score: 5, Funny

    So the polytheists were right? :P

  5. The most wonderful exclamation in science by overshoot · · Score: 5, Insightful

    is not, "Eureka!"

    It's "What the fuck?"

    --
    Lacking <sarcasm> tags, /. substitutes moderation as "Troll."
    1. Re:The most wonderful exclamation in science by Anonymous Coward · · Score: 5, Interesting

      I agree. I was actually annoyed that they found the Higgs where they predicted it to be. That meant that the Standard Model was all wrapped up, but without any sort of loose threads which we could pull to work out wtf was up with quantum gravity, or dark matter and dark energy. (Like the way the photoelectric effect and the ultraviolet paradox were the loose threads that lead to quantum mechanics.)

      It would be really exciting if this result was real, and there's something funky about the Higgs which means the different experiements are detecting it at different masses. It might give us the kick in the pants we need to better understand the universe.

      That said, it's probably going to be something banal like a miscalibrated detector shim, or an unaccounted-for term in one of the equations ... but a geek can hope.

    2. Re:The most wonderful exclamation in science by dreamchaser · · Score: 3, Insightful

      It didn't mean the Standard Model was all wrapped up. It meant what we currently understand of the what we call the Standard Model was wrapped up. That never precluded solving any of the other 'wft' problems you mention with new physics down the road. Models can fit within new models.

    3. Re:The most wonderful exclamation in science by The+Master+Control+P · · Score: 5, Interesting

      The problem is that if there is no New Physics in the Higgs, the next stage where we predict New Physics is the strong force unification scale that would require an accelerator a trillion times more powerful than the LHC to explore. We're talking a particle accelerator the diameter of the asteroid belt.

      But there's still hope in the TeV-per-parton scale the upgraded LHC will be able to reach in terms of finding what keeps the Top mass in check. Plus, dark matter's got to be made of something goddamnit, and it's hopefully not just cold neutrinos.

      And of course, there may be new shit that we haven't even considered yet!

    4. Re:The most wonderful exclamation in science by DamnStupidElf · · Score: 2

      We're talking a particle accelerator the diameter of the asteroid belt.

      Shouldn't be too hard; put the beam deflection electromagnets in orbit and just shoot the beam through the vacuum of space. Not quite a ringworld, but close enough for me.

    5. Re:The most wonderful exclamation in science by maxwell+demon · · Score: 3, Interesting

      I think with "ultraviolet paradox" he meant the problem Max Planck solved, that with classical physics you'd calculate the intensity of thermal (black body) radiation to always grow with growing frequency, giving rise to infinite total thermal radiation. Planck solved that problem by introducing the quantum hypothesis, that radiation energy can only be emitted in fixed portions proportional to the frequency.

      The problem I think you are referring to is a problem in quantum field theory where certain integrals diverge, and which is solved using renormalization.

      --
      The Tao of math: The numbers you can count are not the real numbers.
    6. Re:The most wonderful exclamation in science by mikael · · Score: 2

      Maybe there is a different gravitational field due to different terrain. CERN had a problem where their guide beams would go off target depending on the time of day. Turned out the moon was actually causing distortion to the surrounding land by a few metres, just like water tides. That was enough to change the shape of the collider ring.

      --
      Vintage computer adverts: http://www.vintageadbrowser.com/computers-and-software-ads
    7. Re:The most wonderful exclamation in science by wonkey_monkey · · Score: 3, Insightful

      Turned out the moon was actually causing distortion to the surrounding land by a few metres

      Holy crap. We had to build the LHC to notice this?

      Are you sure it wasn't more like millimetres?

      --
      systemd is Roko's Basilisk.
    8. Re:The most wonderful exclamation in science by mikael · · Score: 4, Informative

      The collider beams go off by a few millimetres. Oceans go up and down by as much as several meters.

      http://science.slashdot.org/story/12/06/08/222247/how-the-moon-affects-lhc-operations

      http://www.quantumdiaries.org/2012/06/07/is-the-moon-full-just-ask-the-lhc-operators/

      http://www.lhup.edu/~dsimanek/scenario/tides.htm
      The "tidal trivia" summary below puts things into perspective. The so-called equatorial bulge due to the Earth's axial rotation lifts the equator about 23 kilometer. The moon's gravity gradient lifts water mid-ocean (where the ocean is deep) no more than 1 meter, that's 1.6 x 10-7% of the Earth radius. Why do we fuss about this? Because over an ocean of large area, that represents a very large volume of water. Also, it's the driving mechanism that controls the periods of the much larger tides at shorelines.

      --
      Vintage computer adverts: http://www.vintageadbrowser.com/computers-and-software-ads
    9. Re:The most wonderful exclamation in science by ceoyoyo · · Score: 2

      Don't worry, the standard model still has LOTS of loose threads:

      http://en.wikipedia.org/wiki/Standard_model#Challenges

      The Higgs itself exacerbates one.

  6. Gods' particles by Anonymous Coward · · Score: 2, Informative

    I fixed the title for you.

    1. Re:Gods' particles by Anonymous Coward · · Score: 2, Funny

      As in, the left particle is a bit larger and lower?

  7. Probably chance by Carnildo · · Score: 5, Informative

    2.7 sigma isn't actually that much: assuming a Gaussian distribution of data, it's a one-in-a-hundred chance of being randomness rather than a real difference (or in other terms, about one experiment in a hundred will generate a false signal). For comparison, the standard for announcing a new particle is 5 sigma (1 in 1.7 million chance of it being a false positive).

    --
    "They redundantly repeated themselves over and over again incessantly without end ad infinitum" -- ibid.
    1. Re:Probably chance by Chuckstar · · Score: 3, Insightful

      Yes. But 1:100 still means that it is probably more likely to be a systematic error. I think about it as asking the following question: "Is the probability that there is a systematic error of this magnitude in ATLAS or CMS greater or less than 1:100?" Considering the complexity of the systems, I would tend to think the probability of that kind of error being systematic is better than 1%.

      In other words, in order for random error to be more likely, ATLAS and CMS both need to be accurate at measuring collision results in an energy range that we've never measured before, to an accuracy of better than 99%... and that accuracy range needs to include all of the numerical analyses and modeling assumptions that are used to build up from the experimental results to the final conclusion. That seems like a pretty high bar to me. (Neither experiment just dumps out a number that is the mass of the Higgs boson. Both require interpretation of experimental results to get to the mass. Errors in the interpretation process need to be part of that 99% number.)

  8. Made me think of my Prof. by noobermin · · Score: 5, Interesting

    So, I'm working on a cutesy undergraduate project with a physicist who works at the LHC (he is involved in a group searching for supersymmetry, so his primary work isn't the Higgs, but yeah). The project is a prototype for a new photo-detector.

    In any case, I finally got the data acquisition working just a few days ago, (it uses a maple, a sort of a faster arduino. I just use the usb serial thingy, and 'cat' and file redirection, lol) so I ran and took some data counting hits from cosmic rays and with some easy python scripting to parse the output, I had a nice rough estimate of cosmic ray flux over my detector. I did a quick wiki search, and found a rate that was within the order of my result, so I typed up a mini report and emailed him my quick and dirty results while noting they were just that, quick and dirty. I was actually kind of proud of myself.

    But, then he sent back this email, if I may quote him:

    Thanks for the update. The approach of checking whether the coincident rate makes sense is a good step, but you need more information. Imagine, for example, that no one had every measured this before. Then, instead of checking if your answer is compatible with Wikipedia, we would be preparing to publish the measurement, and staking our reputation on its validity. In that case, we'd want to do a variety of things to be convinced that it is correct. I can imagine a couple of things to do[...]

    And he listed a number of things try so I can be really sure of my measurements.

    Think about this, the ATLAS guys could have announced the possibility of two peaks in their data and blown our frickin heads off into outer space after having already blown them off our shoulders with the Higgs, but they didn't because it wasn't a sure bet, as TFAs say...it could be background, it could be statistical fluctuations... In any case, there is something very wise about physicists and scientists in general who are often very cautious and untrusting about their measurements and are more than willing for you to double check their measurements and prove them wrong. Well, it could just be for reputation's sake. Whatever the motivation, I think this is one of the strengths of the scientific method and thus, one of the reasons for its success: we aren't quick to publishing until it is just right, and therefore, perhaps our best approximation of the "truth" we can muster.

    This is not to take away from the times when certain people forget to tighten their fiber optic cables...but actually, that works wonderfully for my point...I sometimes feel impatient when I hear, "we're not quite sure yet" or ,"it's only preliminary" from some of these reports and I imagine some of you might too. Nonetheless, science isn't really star trek where you make a discovery, get locked into a phaser fight with it, and make peace in an hour time frame. It is a slow, careful process that at the end, as we see, yields good results in technology and the advances we have today. Therefore, it's worth the wait. So, have some patience, my reputation is on the line.

    1. Re:Made me think of my Prof. by scheme · · Score: 3, Insightful

      Whatever the motivation, I think this is one of the strengths of the scientific method and thus, one of the reasons for its success: we aren't quick to publishing until it is just right, and therefore, perhaps our best approximation of the "truth" we can muster.

      On the other hand: What if you did publish your work early and often, not as concerned with slowly and deliberately ensuring everything is just right before spreading the information -- Not keeping quiet just so that you can be the one with the badge of "1st"? Why, then worldwide cooperation could kick in. Perhaps other interested parties would help you prove or disprove the results much more quickly. Thus, accelerating the speed of scientific progress. Now, don't get me wrong. I'm not saying it's wrong to not publish things that you aren't absolutely sure about, just that what you're doing seems really strange to me. Have you questioned your information dissemination methods? A good scientist would... Why, there could have been times that you were wrong about being wrong, i.e. made a discovery but never known it too... Perhaps it's time to re-think the system of publishing altogether?

      The problem is that most early results are incorrect and after doing some checking, it turns out they were systematic errors or mistakes or something similar. If everyone published early and often, you'd get so many results (with most of the results being incorrect) that no one could track it to figure out which results were interesting and worth investing the time and effort to work on. Duplicating someone else's work takes a lot of time and effort and may involve building a lot of stuff or flying to another lab to learn new techniques. Unless you're really sure that the results are likely to pan out, why would anyone spend tens of thousands of dollars or a few months at another lab learning a technique?

      The costs and startup efforts are much higher for most sciences unlike code so open source techniques won't work as effectively. It's effectively like having to reimplement a good portion of a piece of software before you can start contributing.

      --
      "When you sit with a nice girl for two hours, it seems like two minutes. When you sit on a hot stove for two minutes, it
    2. Re:Made me think of my Prof. by LourensV · · Score: 3, Insightful

      Whatever the motivation, I think this is one of the strengths of the scientific method and thus, one of the reasons for its success: we aren't quick to publishing until it is just right, and therefore, perhaps our best approximation of the "truth" we can muster.

      On the other hand: What if you did publish your work early and often, not as concerned with slowly and deliberately ensuring everything is just right before spreading the information -- Not keeping quiet just so that you can be the one with the badge of "1st"? Why, then worldwide cooperation could kick in. Perhaps other interested parties would help you prove or disprove the results much more quickly. Thus, accelerating the speed of scientific progress.

      You are assuming that scientists only ever communicate by publishing papers in journals. That's incorrect, there is a lot (and I mean a lot) of informal communication and collaboration, by email and phone and through presentations and posters at conferences. Our knowledge is now so vast and much research being done so multidisciplinary that it's nearly impossible for any single person to know enough to really cover all the aspects of a particular investigation. In my field, you'd need to be a good programmer, an expert statistician, an experienced and knowledgeable (field- and theoretical) biologist, and a good systems analyst/modeller. Such people don't exist, so work is done in teams with each member contributing their specific expertise. When you get a weird result, you go and talk to your colleague about it, and try to figure it out together, and you keep going together until you feel that you really understand what's going on. And then you write the paper, it gets published, and then hopefully it won't turn out to have been a fluke or a mistake or not representative of the wider area of research. If the whole team can't figure it out, you might publish a "Hey, that's weird?" paper, as was done here.

      If people published everything they did immediately, we'd get so many publications that it would be impossible to keep up with all of it. The whole situation would be similar to the "Linus doesn't scale" problem in Linux kernel development a few years ago, where Linus Torvalds was inundated with patches and couldn't keep up. They solved that by appointing lieutenants, who filter and aggregate contributions. Publishing papers works the same way, you solve the smaller problems locally, and publish bigger and better-vetted results, so that everyone else doesn't waste their precious time on solving other people's small problems and consequently invalid results. Also, people wouldn't waste their precious time on writing up all those small problems, and peer-reviewing them, and so on. Writing a paper is not like writing a post on the Internet (something that some climate change deniers often conveniently forget), it takes serious time and effort by a group of people to make sure that the results are really of good enough quality. You don't want to waste that effort on trivial things.

  9. Re:We need yet another Einstein by Sulik · · Score: 2

    Dude, I understand the impatience/frustration due to the slow progress of physics in past 40 or so years, but if I understand you correctly, you're seriously suggesting to sit on our asses and do nothing just waiting/praying for the next Einstein to turn up ? I'm also on the opinion that the Standard Model is a bit like curve-fitting experimental results, and it does (obviously) work with observation around the range it was designed for (and we already know it fails outside of that, but still definitely useful in practice), but the best thing we can do IMO is to push experiments further and further to try to find discrepancies which will make it easier to come up with new theories, which is exactly what is going on at the LHC and many other places around the world. The next revolution might very well come out of a totally different field ~ personally I'm hoping that exascale computing will make it easier to test new theories (being able to accurate simulate entire organs at the molecular level could revolutionise medicine, advances in quantum chemistry could also [in]validate some theories and have plenty of practical implications).

    --
    Help! I am a self-aware entity trapped in an abstract function!
  10. If wishes were particles by Roger+W+Moore · · Score: 4, Insightful

    Using bigger and bigger colliders, we can virtually create any particule with any property that fix the equations.

    I think you are ascribing far too much power to us particle physicists! We don't get to create whatever particle we want we can only create ones that can exist. What is remarkable is that the ones we think exist to solve inconsistencies actually turn out to be there. This means that our extrapolations from existing physics are extremely good at predicting new physics. In fact there are already theoretical models, such as supersymmetry (SUSY) which predict 5 Higgs bosons, two of which are charged...

  11. Re:Bahh by Dexter+Herbivore · · Score: 2

    "Through every rift of discovery some seeming anomaly drops out of the darkness, and falls, as a golden link into the great chain of order." Edwin Hubbel Chapin

  12. Re:We need yet another Einstein by wonkey_monkey · · Score: 2

    Do you even have a frigging clue how the periodic table works?

    Do you even have a frigging clue what sarcasm looks like?

    --
    systemd is Roko's Basilisk.
  13. Re:Accuracy by wonkey_monkey · · Score: 4, Interesting

    I'm pretty sure their huge device is just not accurate enough.

    Of course! This would surely not have occurred to the particle physicists who built and operate the machine and published these results. It's a good job there are people like you who read about things on the internet and therefore know more than they do.

    Two separate measurements can give different results based on how they configured the device.

    I think they did a few more than two measurements, and I doubt they're dumb enough to go fiddling with the detector in the middle of a run.

    Damn floccinaucinihilipilificationists...

    --
    systemd is Roko's Basilisk.