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Science

Higgs Data Offers Joy and Pain For Particle Physicists 186

Posted by samzenpus from the good-and-bad dept.
scibri writes "So now that we've pretty much found the Higgs Boson, what's next? Well: 'There's going to be a huge massacre of theoretical ideas in the next couple of years,' predicts Joe Lykken, a theoretical physicist at Fermilab. The data has shored up the standard model, but technicolor is dead and supersymmetry is starting to look pretty ropey now. Theorists are now poking at the mathematical chinks in the standard theory in the hopes of being the first to find a deeper truth about how the Universe works."
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Higgs Data Offers Joy and Pain For Particle Physicists More

Higgs Data Offers Joy and Pain For Particle Physicists

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  • Stopped reading at "Mathematical chinks" (Score:2, Funny)

    by Anonymous Coward

    C'mon slashdot, you're better than that.

    Yes I'm being funny (or trying to).

  • Did we really find it? (Score:3)

    by EdIII ( 1114411 ) on Thursday July 19, 2012 @07:03PM (#40706025)

    From what I understand it was only one single experiment that showed us something that we think is where/what the Higgs Boson would look like.

    Has it been reproduced or confirmed?

    Scientists using the Large Hadron Collider in Geneva have announced the discovery of a new subatomic particle to very high confidence that is consistent with what we expect the Higgs particle to look like.

    That's not very definitive. Can anybody else around well versed in particle physics tell us if the Higgs has really been found or not?

    • From what I understand it was only one single experiment that showed us something that we think is where/what the Higgs Boson would look like.

      Has it been reproduced or confirmed?

      Not yet, but soon!
      I'm building my very own Large Hadron Collider in my backyard in order to try to reproduce the results.
      Of course I don't have superconducting magnets, but I'm hoping that by using ALL the the letters of the alphabet I can get close enough to the required field strength.

    • Re:Did we really find it? (Score:5, Informative)

      by Goaway ( 82658 ) on Thursday July 19, 2012 @07:08PM (#40706077) Homepage

      It is not confirmed, but it is not expected to not be confirmed, so nothing lost by starting on the theoretical work ahead of the confirmations. In the unlikely case it turns out to be something else, we can just start over.

      • In the unlikely case it turns out to be something else, we can just start over.

        So we can spend millions of dollars, and perhaps billions if a huge linear accelerator is built, going down the wrong track instead of waiting a few months or years to confirm the single experiment. IResearch funding should be spent on confirmation rather than advancement based on a single experiment.

        • The difference isn't where funding will go. This will impact what the theoreticians are doing for a year or two if it doesn't end up getting confirmed. The primary cost in that context will be for chalk and erasers.

          • This is either a troll or you really do not understand the costs of theoretical research. If it is the former then you got me. If it is the latter then here are a few more costs to consider;
            1. Wages of the PHDs.
            2. Wages of the grad students helping the PHDs.
            3. Administration costs for above payroll.
            4. Costs of lab space.
            5. Costs of computer time for simulations.
            A two year research project with a team of 2 professors and 4 grad students could easily run over a couple of million dollars. If many universities

            • Re:Did we really find it? (Score:5, Funny)

              by Stuarticus ( 1205322 ) on Friday July 20, 2012 @03:43AM (#40708923)
              Stupid universities wasting time and money trying to advance human knowledge. They could use that money to.............. Buy a tomahawk missile?

              • Now that is either a troll or a very stupid poster. I prefer to give the benefit of the doubt and go with the former.

            • No, I understand them just fine thank you. It is possible that I misjudged how my statement would be interpreted. I didn't expect it to be read quite so literally. The point is that theoretical research is comparatively cheap compared to building new particle accelerators, which your earlier statement specifically talked about building. You are talking about costs that are at least an order of magnitude smaller. And what would you have those PhDs and grad students do in the meantime? To be ready to actually

              • You are talking about costs that are at least an order of magnitude smaller.

                An order of magnitude less than horrendously expensive it still very expensive.

                And what would you have those PhDs and grad students do in the meantime?

                How about working on the data from the current experiment to prove it rather than assuming it proves the theory. Isn't there other things to work on in theoretical physics rather that work based on the unproven existence of Higgs bosun?

                I think I see where we diverge in our ideas. I see a huge difference between a theoretical physicist and theoreticians. To me theoretical physicists takes proven fact and theorizes one or two level

        • Re: (Score:2)

          by Goaway ( 82658 )

          You seem to have missed the word "theoretical" in my post.

          • Theoretical research still takes people and computers; both of which cost money. A research team consisting of two PHDs and four grad students can easily cost $1Mill. a year. Multiply that by the number of interested research groups and the possible waste can be huge. Are you really willing to risk wasting millions of dollars in very scarce funding for theoretical research just because one can not wait to be sure that the single experiment was not an anomaly?

            Here is a quote from CERN Director General Rolf H

            • Re: (Score:2)

              by Goaway ( 82658 )

              You are exaggerating to an incredible degree here.

              You think those people wouldn't be paid if they weren't working on the Higgs results?

              • You are exaggerating to an incredible degree here.

                What exactly do you consider to be exaggerations?

                You think those people wouldn't be paid if they weren't working on the Higgs results?

                How about we pay them to work on something based on a more proven theory rather than, what is at this point, yet another layer of conjecture. How many layers of conjecture does it take to change from theory to flight of fancy? If this is true and this is true and this is true and this is true and this is true then this could be true.

                • Re: (Score:2)

                  by Goaway ( 82658 )

                  I have no idea what you are even talking about any longer.

                  This is a first experimental verification of a theoretical result. It fits what was expected. It is not enough for a solid confirmation yet, but for it to be false would be quite unexpected and surprising. We are not expecting further experiments to disprove this.

                  Why are you so upset over a tiny little chance that maybe this will turn out to be a different particle, and that a few professors would have wasted a couple months of work on that?

                  • Why are you so upset over a tiny little chance that maybe this will turn out to be a different particle, and that a few professors would have wasted a couple months of work on that?

                    That assumes a couple of things;
                    1. That it will take only a couple of months to replicate and prove. It may take years especially if funding get diverted to post-Higgs bosun study.
                    2. That their estimates of probability are actually correct. From the article they stated that if one sensor detected decay as predicted for a Higgs bison it was 90% probability that it was one. Later they state that since two detected the decay simultaneously the probability goes up to 99.999%. From elementary probability if one

                    • Re: (Score:2)

                      by Goaway ( 82658 )

                      That it will take only a couple of months to replicate and prove. It may take years especially if funding get diverted to post-Higgs bosun study.

                      What funds are going to be diverted? Are we suddenly going to start paying professors more money?

                      Also, if you can't even spell "boson", are you really sure you are qualified to talk about the value or likelihoods of these results?

                    • If professors who are currently working on proving that the Higgs boson exists accept the current theory that it does as fact they may move to new research based on that assumption. So instead of continuing to work to prove the existence of the Higgs boson they are spending their research dollars on something else. That is how finding gets diverted.

                      The experiment has not even been replicated. There could have been some flaw that created false results like the faster than light experiment done by the same or

      • It is already confirmed as 2 LHC's detectors (ATLAS and CMS) obtained the same result. This is the main raison why there are these 2 detectors instead of just 1. The team of physicists are different, so are the framework and analysis involved in the discovery.

    • Re:Did we really find it? (Score:5, Informative)

      by insecuritiez ( 606865 ) on Thursday July 19, 2012 @07:39PM (#40706313)

      It's unknown but really likely. There is definitely a particle at around 125 GeV but there certainly is a (very small) chance it could be something else.

      The standard model predicts a number of different ways the Higgs Boson can decay and what probability it has for each type of decay.

      The most common easy to measure decay modes are:
      Higgs -> Two Photons (high energy gamma rays)
      Higgs -> Two W Bosons -> 4 leptons (electrons or muons)

      So what they are actually seeing is the decay products and they measure the energy of each component of the decay and add that up to find the original energy of the Higgs.

      The measurement of the two photons is called the "gamma-gamma" channel or "diphoton" channel. They call the 4 lepton channel the "golden channel" because it's a pretty clean signal with a low "background" (noise). That is, they get a good signal to noise ratio from the 4 lepton channel.

      The theory says that the two photons should happen a certain % of the time and the 4 leptons should happen a different % and the other decay modes should happen with other probabilities.

      One of the reasons to believe they have found the Higgs boson and not some other particle is that the decay relative rates for each type of decay are pretty close to what the theory suggests.

      The best way to study the Higgs would be to produce lots of them accurately without producing other particles. The best-known way to do that is with a linear collider that smashes leptons (usually electrons) together. They can tune the energy of the collisions to the exact value to produce Higgs. This is how the W boson was studied so accurately at SLAC. A new international linear collider (ILC) would need to be built to reach the energy levels needed to make the Higgs. Luckily, it's a pretty low and easy to reach energy compared to what it could have been which makes an ILC somewhat reasonable to build.

      • A new international linear collider (ILC) would need to be built to reach the energy levels needed to make the Higgs.

        . . . so we built a billion dollar ring, that told us, that we need a straight line . . .

        Brilliant!

        • Re:Did we really find it? (Score:5, Informative)

          by insecuritiez ( 606865 ) on Thursday July 19, 2012 @07:57PM (#40706457)

          The LHC was built to find any new physics, not just the Higgs. The fact that we've been able to rule out SUSY for large mass ranges is part of that. To measure the specific properties of one particle though does need something a bit more purpose-built. They'll be able to measure a lot about the Higgs boson but not anywhere near as much as a linear collider could measure.

          Also, for part of the year they stop injecting protons and instead inject lead nucului. This is meant to measure extremely messy but very high energy collisions that should generate quark-gluon plasmas.

      • Decay channels not rates (Score:5, Informative)

        by Roger W Moore ( 538166 ) on Thursday July 19, 2012 @08:43PM (#40706719) Journal

        One of the reasons to believe they have found the Higgs boson and not some other particle is that the decay relative rates for each type of decay are pretty close to what the theory suggests.

        Actually that is not really true because we do not have enough statistics to measure these rates with any accuracy. In fact the "most likely" value for diphoton rates for both ATLAS and CMS are quite a bit higher than the Standard Model predicts but the accuracy is sufficiently low that they are not yet inconsistent with the SM values. So really the rate measurements are currently far too inaccurate to have any idea whether this is a Higgs boson or not but things are improving rapidly as we gain statistics.

        What is far more important at the moment are the decay channel observations. Since it decays into photons, W and Z bosons we know it must be either a spin-0 or spin-2 particle and it cannot be a fermion (spin-0.5). The Higgs should be spin-0 so this is consistent but not conclusive. Essentially it decays into the particles it should do and it _potentially_ has the correct spin. We can get a more accurate determination of the spin i.e. whether it is spin-0 or spin-2 by looking at the angle between the two leptons (electron or muon) produced in the WW decay channel - expect results from ATLAS and CMS on this soon.

        However by the end of the year the rate measurements should be a lot more accurate and things will possibly start to get interesting if the current diphoton rates stay where they are but we end up with less uncertainty on the measurement.

      • Re: (Score:2, Insightful)

        by Anonymous Coward

        A few corrections:

        Higgs -> Two W Bosons -> 4 leptons (electrons or muons)

        This is actually H -> ZZ -> 4 leptons [wikipedia.org]

        This is how the W boson was studied so accurately at SLAC.

        I believe this is also incorrect. The W boson was discovered at Gargamelle and studied at LEP, CERN.

    • Re:Did we really find it? (Score:5, Informative)

      by bledri ( 1283728 ) on Thursday July 19, 2012 @07:41PM (#40706333)

      From what I understand it was only one single experiment that showed us something that we think is where/what the Higgs Boson would look like.

      Has it been reproduced or confirmed?

      ...

      That's not very definitive. Can anybody else around well versed in particle physics tell us if the Higgs has really been found or not?

      I think that the announcement is based on a couple of years of data collected by two different teams using different methods, so calling it a single experiment seems a bit of an over simplification. See Higgs Discovery: The Data [profmattstrassler.com] blog entry by Matt Strassler.

    • Pink elephants (Score:5, Informative)

      by WallaceAndGromit ( 910755 ) on Thursday July 19, 2012 @08:49PM (#40706767) Homepage
      This is worth a watch...
      http://vimeo.com/41038445 [vimeo.com]
      Enjoy!
    • The data obtained by two independent experiments (CMS and ATLAS, both at the LHC) is in excellent agreement for the mass of the particle. The results are also coherent with those obtained by two experiments (CDF and D0) based at the Fermilab. Something has been found, with a very high statistical relevance (five sigma level, so there is only a chance in a few million that this is a fluctuation). Whether this something is indeed the Higgs boson as predicted depends on its detailed behaviour, so it will take
    • The higgs has definitely not been found. They only found a particle that looks like the higgs at some mass. If you saw the conference that announced the new "particle" none of the people behind the table said that they found the higgs, they kept on repeating that they found a new particle. To verify whether or not it is the higgs, you need to study the individual channels and verify if they belong to a higgs interaction or not ( and this will take time ). But I repeat we have no proof that this is the higgs

    • Re: (Score:2)

      by PiMuNu ( 865592 )

      No it was really two separate, independent experiments, CMS and ATLAS. Both reported discovery independently at the 5 sigma level (10^-5 probability of error or whatever it is). Both discovered a particle at the same mass, within experimental error. There was no shared knowledge or data between the analysis teams. They were working on the same accelerator (LHC), but at different points in the ring, so no cross talk or anything is possible between the two experiments (several km of rock in the way). The on

    • Re:Did we really find it? (Score:4, Informative)

      by Anonymous Coward on Friday July 20, 2012 @03:02AM (#40708703)

      only one single experiment

      Actually, it was two different experiments: CMS [wikipedia.org] and ATLAS [wikipedia.org]. The LHC is the big ring-like structure that accelerates particles around it; CMS and ATLAS are two detectors at different points on that ring that watch as the particles collide with each other. Both CMS and ATLAS have detected a new particle, with the same mass (~125 GeV), with about the same significance (~5-sigma, or about a 1-in-50-million chance of getting that result by chance).

      The mass is about what the standard model of particle physics predicts for the Higgs boson, so it looks very much like this new particle is it. But the physicists are being careful not to state outright that they've found it, because there are certain properties that the Higgs is expected to have - charge, spin and parity, I think - which they haven't been able to measure yet. When they've got enough data to measure those, and if they match what the Higgs is supposed to have, then they'll state that they've definitely detected it.

    • I was always dissatisfied by string theory to be honest. Not from the science per se but from the philosophical implication that after you wade through all the scales there actually exists one distinct smallest and one distinct largest scale.
      I mean, come on! The Universe can do better than that! And what about recursion? Huh that is a bit poetic at least!

    • Oh no, that isn't true. The Higgs Boson is a small but consistent data blip in a multitude of a huge number of experiments. Its only been found in this one collider though so the blip in the data could be due to an issue in the equipment.
      http://theskepticalteenager.files.wordpress.com/2012/07/higgsbosongraph1.png [wordpress.com]
      As the Input Energy of the collisions changed the expected output of the collisions changed following a predicted exact graph. The Higgs Boson is predicted to alter that straight curve at an exact s

    • "From what I understand it was only one single experiment that showed us something that we think is where/what the Higgs Boson would look like.
      Has it been reproduced or confirmed?"

      CMS and ATLAS are TWO like 2 independant experiments. So, yes, if data in both experiments converge to the same conclusion, it would have been confirmed and reproduced. Physicists aren't idiots and this is the reason they are running two different experiments with the same goal and working in isolation to each other.

      Now, the poi

  • I, for one, will pull my hand back from that pair of trousers!

  • Really? (Score:5, Funny)

    by amicusNYCL ( 1538833 ) on Thursday July 19, 2012 @07:05PM (#40706051)

    Theorists are now poking at the mathematical chinks

    I realize Asians are known for excelling at math, but do we really have to bring race into this?

    I'm very, very sorry. I couldn't resist. I understand I'm a terrible person, you don't need to reply and tell me that.

  • The real takeaway (Score:5, Insightful)

    by 93 Escort Wagon ( 326346 ) on Thursday July 19, 2012 @07:24PM (#40706233)

    I predict, over the next two years, what's going to come out of this is the following:

    Physicists will have poked holes in most all the prevailing Standard Model-compatible theories, and will start talking about the inadequacies of the LHC and how we need a much bigger collider to prove or disprove the existence of those elusive super-partner particles required by supersymmetry.

    • More like, we will find that quantum physics and standard model don't actually differ, but only in observation.

      • Re:The real takeaway (Score:5, Informative)

        by Guy Harris ( 3803 ) <guy@alum.mit.edu> on Thursday July 19, 2012 @08:24PM (#40706605)

        More like, we will find that quantum physics and standard model don't actually differ, but only in observation.

        They differ by virtue of belonging to different categories of things.

        Quantum physics is a general framework that encapsulates a number of particular physical theories, including quantum electrodynamics (interaction between charged particles and photons), quantum electroweakdynamics or whatever it's called (throw in the W and Z bosons and neutrinos on top of quantum electrodynamics), quantum chromodynamics (interaction between quarks, bearing a charge called "color", and gluons, the force quanta for the field generated by that charge), and the standard model (quantum electroweakandchromodynamics). So the standard model is a quantum theory, and thus falls under the general heading of "quantum physics" (as do atomic physics, nuclear physics, most if not all of what's called "condensed matter physics", and so on).

        • While you can SM = Quantum Theory, the Standard Model is badly *incomplete*.
          http://en.wikipedia.org/wiki/Beyond_the_Standard_Model [wikipedia.org] ... needed to explain the deficiencies of the Standard Model, such as the origin of mass, the strong CP problem, neutrino oscillations, matterâ"antimatter asymmetry, and the nature of dark matter and dark energy. Another problem lies within the mathematical framework of the Standard Model itself â" the Standard Model is inconsistent with that of general relativity to t

    • If the next step in discovering what makes the world around us tick involves a slightly larger tunnel, I'm all for it.

  • You can't kill SUSY (Score:5, Interesting)

    by Anonymous Coward on Thursday July 19, 2012 @07:42PM (#40706343)

    Every new discovery of the past few decades has supposedly "killed" SUSY, but every time it makes a comeback with a modification to avert whatever problem the observation caused. Other theories do the same, to a slightly lesser extent.

    I don't see why Technicolor is dead. The Nature article makes the claim that it's because Technicolor is Higgsless, but that's something of a falsehood. Technicolor lacks an elementary Higgs, because the role played by the elementary Higgs in the Standard Model is instead played by a composite particle. As far as I can tell it's perfectly possible that the bosonic state at 125GeV is a composite rather than elementary Higgs.

    (FD: I'm a PhD student with a thesis area based around technicolor)

    • Every new discovery of the past few decades has supposedly "killed" SUSY, but every time it makes a comeback with a modification to avert whatever problem the observation caused.

      Which just goes to show that supersymmetry theorists are very adept at predicting the past.

  • I understand that it would be frustrating to see years of labor on a theory go down the tubes, but at its root the finding means that we now have a slightly better understanding of reality. I would think that for many if not most people in the field, if the implications are as stated in the summary, this is exciting because we have a better idea of what direction to theorize in. Falsification is just as if not more important than making hypotheses.

    • Every baby that dies is a win for evolution. But that's not how the baby sees it at all, nor the parents!

    • Re: (Score:2)

      by gr8_phk ( 621180 )

      I understand that it would be frustrating to see years of labor on a theory go down the tubes, but...

      Ever since relativity and quantum theory came along, a lot of physicists have been looking for nifty or non-intuitive explanations for things. They keep looking for unexpected stuff in contrast to the "standard model". You know "new physics" is a common term and probably helps to get funding. The more exotic hypothesis (I won't give them the satisfaction of calling them theories) have been people hoping for

  • consistent with The Higgs Boson

    The short version of what scientists are *actually* saying boils down to:

    We theorised where IT would be and when we finally looked THERE we found SOMETHING which isn't Absolutely Not IT.

    Reports I've read (forgot URLs, sue me) indicated the result found was NOT exactly as expected, but also not so massively different that they'd be sure it was NOT The Higgs.

    More like:
    Scientist1: Yup, that's the Higgs!
    Scientist2: But I thought you said it'd have black spots not very very dark brown.
    Scientist1: Well if we'd solved everything then what are we going to do after that?

  • Holy crap (Score:5, Funny)

    by PopeRatzo ( 965947 ) on Thursday July 19, 2012 @09:33PM (#40707065) Journal

    "Higgs Data Offers Joy and Pain for Particle Physicists"

    "Joy and pain"? Jesus, what are they doing, tying the boson in a knot and putting it up their bums? (I guess it would have to be a "boson's knot").

    Instead of the God Particle, they could call the "Oh God! Particle".

    [note: I only make this kind of off-color joke because it's past 9pm and the children have all gone to bed. I call this the "safe harbor" hours, when normal FCC rules moderating online behavior are relaxed, like a sphincter with a Higgs Boson in it. Thanks to these safe harbor rules, constitutionally-protected free speech rights of adults are balanced with the need to protect children from harmful content, like the word "fuck" and references to tying massive particles in knots and putting them up one's bum and then pulling it out slowly as climax is achieved (thus the expression "string theory"). Two physicist doing this while standing face to face are called a "Hardon Collider", named for the famous Scottish physicist Sir Ivan Hardon (1847-1903) who first posited that there's nothing else to do while waiting for the experiment to finish and there were so few female physicists back then that, hey, what happens in the lab stays in the lab. Tragically one of his experiments exploded while Hardon and a lab assistant were engaged in this act of outrage and since they had their pants down both of them got kilt.]

    • Re: (Score:2)

      by Halo1 ( 136547 )

      Instead of the God Particle

      Don't call it that, you fool [youtube.com]!

      Tragically one of his experiments exploded while Hardon and a lab assistant were engaged in this act of outrage and since they had their pants down both of them got kilt.]

      Thank Science for the random Scotsman when you're in need! (I'm not sure whether that was on purpose, but if it was: very nice!)

  • from every other article I've read on the topic, which say that the measured mass of the Higgs boson is exactly where it should be if the Minimally Supersymmetric Standard Model is correct; and too low for any non-supersymmetric theory.

    http://motls.blogspot.com/2012/07/why-125-gev-higgs-boson-isnt-quite.html?m=1 [blogspot.com]

  • Duhhhhh now we need an even bigger, costlier particle accelerator!

    • Re: (Score:2)

      by Magada ( 741361 )

      The LHC is that bigger and costlier accelerator. It's being run at way less than nominal power right now.

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