Researchers Find Evidence of How Higgs Particle Imparts Mass 91
brindafella (702231) writes Physicists at CERN's Large Hadron Colider (LHC) ATLAS experiment have been looking through their data, and have found enough of the extremely rare "W boson" (proton-proton) collisions that they can now declare their results: They have found how the Higgs imparts mass to other particles. From the article: "'Only about one in 100 trillion proton-proton collisions would produce one of these events,' said Marc-André Pleier, a physicist at the U.S. Department of Energy's Brookhaven National Laboratory who played a leadership role in the analysis of this result for the ATLAS collaboration. 'You need to observe many [collisions] to see if the production rate is above or on par with predictions,' Pleier said. 'We looked through billions of proton-proton collisions produced at the LHC for a signature of these events—decay products that allow us to infer like Sherlock Holmes what happened in the event.' The analysis efforts started two years ago and were carried out in particular by groups from Brookhaven, Lawrence Berkeley National Laboratory, University of Michigan, and Technische Universität Dresden, Germany."
Here's a pre-print of the paper.
like donut holes (Score:5, Funny)
The higgs particle imparts mass the same way that donut holes impart mass, but differently.
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Not that differently. I know that I slow down considerably when moving through a field of doughnut holes.
Re:like donut holes (Score:4, Funny)
I believe that effect is also called "Timbit drag"; discovered by the great Canadian scientist Tim Horton. Incidentally, he was also the individual who discovered the effect of non-uniform doughnut hole decay; that is, the tendency of old fashioned plain doughnut hole variants to persist for hours or even days after the glazed or chocolatey variants have long since disappeared.
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They throw out hundreds or thousands of collisions for each datum they keep. So they have billions of events stored as data out of many trillions of mostly-boring collisions so far. This cherry-picked data may have something to do with it.
Re:Erm (Score:5, Informative)
Indeed. Only a small fraction of the collision events are kept, otherwise the amount of data would be overwhelming.
From http://www.lhc-closer.es/1/3/13/0 [lhc-closer.es]:
In particle physics, a trigger is a system that uses simple criteria to rapidly decide which events in a particle detector to keep when only a small fraction of the total can be recorded. Trigger systems are necessary due to real-world limitations in data storage capacity and rates. Since experiments are typically searching for "interesting" events (such as decays of rare particles) that occur at a relatively low rate, trigger systems are used to identify the events that should be recorded for later analysis. Current accelerators have event rates greater than 1 MHz and trigger rates that can be below 10 Hz.
Re:Erm (Score:5, Informative)
"Now with the LHC data in hand, the measured rate agrees with the prevailing theory's predictions and establishes a signal at a significance level of 3.6 sigma—strong evidence, according to Pleier. "The probability for this measurement to be a mere background fluctuation is very small—about one in 6000," he said."
"Again, so far, the data indicate that the Higgs is working as expected.
"For the first time, we can rule out certain models or predictions that we could not before," Pleier said. "To complete the job, we need more data, at higher energy, so we can see the fingerprint more clearly."
The LHC will resume data taking at increased collision energies—13 tera-electronvolts (TeV) instead of 8 TeV—in spring of 2015. The datasets collected will be up to 150 times the size of the currently available data and will allow for a detailed behind-the-scenes look at the Higgs at work." "
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"So if only "one in 100 trillion" collisions produce detectable events, and they've only observed "billions" of collisions, then actually detecting just one is shear luck, and reproducing it is next to impossible......."
I must be that they speak Planet an the submitter speaks Imperial. There's several magnitudes of difference.
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So if only "one in 100 trillion" collisions produce detectable events, and they've only observed "billions" of collisions, then actually detecting just one is shear luck, and reproducing it is next to impossible.......
I guess I'm not understanding something.
They only capture the few collisions that look interesting for further analysis, I don't know exactly what that means but they probably got fingerprints for known, common collision results and discard them immediately. Like a coin flip where you dismiss heads and tails and only look for the WTF events like it landed on the edge, rolled off the table or was snatched in mid-air that doesn't fit any previous pattern.
If mass can be finally explained... (Score:3, Interesting)
Since Einstein's famous equation relating mass and energy, physicists have always still wondered what really gives particles mass. Perhaps soon we will know a theory of mass that does not only boil down to it is a collection of energy. I for one, am hopeful that in my life time, even energy will be better understood, so that the wave particle equation can be further simplified.
Exciting times ahead for sure.
Re:If mass can be finally explained... (Score:5, Funny)
I'm just ready for the Higgs anti-boson diet pill......
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You'll get my bosons when you pry them out of my cold dead hands, you boson-grabbing, anti-boson crusader.
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... physicists have always still wondered what really gives particles mass ...
< Insert "yo mama" joke here. >
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Well, exciting if it leads to something. Say the temporary removal of mass. That would be very interesting (if also quite improbable). More likely it could lead to some purely theoretical advance that could then lead to some currently unexpected result. Perhaps storing information in quark spin states. Perhaps total conversion of mass to energy. Something.
So far, though, it's totally matched theoretical predictions, and that's dull. Also troubling, because we KNOW that current theories are incomplete
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Well, exciting if it leads to something. Say the temporary removal of mass. That would be very interesting (if also quite improbable).
"Improbable" is stating it mildly. If the fundamental particles in a macroscopic object stopped interacting with the Higgs field, they'd still presumably be interacting with each other. The particles wouldn't have any mass, but the nuclei and atoms would still have the vast majority of their mass.
If you got rid of the mutual interaction energy too, then you wouldn't have a macroscopic object any more. (As an added bonus, you'd have proven Asimov wrong experimentally [wikipedia.org].) Instead, you'd have a bunch of quarks a
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I wouldn't have proven Asimov wrong, because I didn't say anything about how much energy it would take to remove the mass, or how long "temporarily" was.
I said it would be very interesting, not useful. Useful is to hope for, not to expect, especially when it comes to changing fundamentals, like temporarily removing mass.
The this is, we don't have a handle on what could be done if mass can be explained. The best guess is that it will totally match current theories. That's not only dull, and useless, that'
Probability fail (Score:1)
It's one-in-trillians chance based on theory and they looked at billions and they found one? What?
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It's one-in-trillians chance based on theory and they looked at billions and they found one? What?
Lucky roll of the dice.... It COULD happen on the first observed collision.... But one must remember that the chances of it happening on the second is exactly the same as on the first and the chance of it happening in either of the two collisions does not add like you'd think.
But your question is valid... Seems pretty unlikely, given the odds... Not impossible, just really unlikely. I'm thinking that their "one in a trillion" theory is off by a few orders of magnitude, but my estimate isn't based on anyth
Another giant leap? (Score:3)
Re:Another giant leap? (Score:5, Insightful)
I think because of the scientific method, you come at it from the other direction.
Someone did some maths. That suggests that it does give matter mass, and in doing so also predicts certain decays.
Then you look for those decays. The chances of those decays occurring completely at random in the exact way your maths predict, in any other circumstance, are immensely small. Thus - if the decays are there - it's probable that you were right.
It's like saying, we know there is a certain kind of Yeti in this forest. The maths tells us that its footsteps will look a certain way, walk so far, stay confined to this area, etc.. And when we and others go looking - eliminating all bias they can - we happen to find footsteps exactly like that, exactly where we expected, exactly how we expected.
Now it doesn't mean it IS a Yeti. It doesn't mean it's even our kind of Yeti. It just means that - from complete assumption and logical consequences of that reasoning, we happen to find exactly what we'd expect if we were right. The chances of us being wrong but something SO SIMILAR happening in the exact right place is immensely tiny and - statistically, predictable enough that you can try to eliminate it as much as possible. This is all that "99.9999%" certainty junk that you see. For things to decay in that way, we're 99.9999% certain that it is because of the original assumption and not anything else along the way (including random chance).
When you come at it, arse-backwards like that, the chances of you being wrong are small. Unless, of course, some other animal that's equally as unknown happens to completely coincidentally make the exact same footprints. In which case, that's STILL a win for maths/science. We found something out by poking around in the right places that we never knew before and - given the similarity - our maths can't have been far wrong in the first place. And we can spot the error, correct for it, and try to understand it.
Nobody is seriously saying "this is EXACTLY what we thought". They are saying, when we test under the assumptions made, the evidence of reality appears to fit this best, subject to a certain accuracy. Other hypotheses that predict similar results in the same area either don't exist (which is suggestive that you're right but still has to be proven) or have to be proved wrong in order to get close to making such statements.
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Now it doesn't mean it IS a Yeti. It doesn't mean it's even our kind of Yeti.
What d'ya mean? Every Yeti is our kind of Yeti. Perhaps the Higgs Boson just needs to leave giant footprints in the snow.
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Now it doesn't mean it IS a Yeti. It doesn't mean it's even our kind of Yeti.
What d'ya mean? Every Yeti is our kind of Yeti. Perhaps the Higgs Boson just needs to leave giant footprints in the snow.
Without the Higgs Boson, there would be no snow... so doesn't that kind of mean that the snow itself is the "footprint in the snow" of the Higgs Boson?
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The Higgs is not responsible for creating mass in general, just for the mass of particles included in the Standard Model. The Standard Model is incomplete since in this model the mass of neutrinos is zero. So the Higgs doesn't explain the mass of neutrinos.
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Even more than that, the Higgs mechanism is not responsible for most of the mass of atoms or nuclei, just the fundamental particles that make them up.
A proton is made from two up quarks and a down quark. Up quarks weigh in at about 2MeV each, and down quarks are about 5MeV. A proton, by contrast, has a mass of 938MeV. So that's about 1% quarks-interacting-with-the-Higgs-field and 99% quarks-interacting-with-each-other.
Re:Another giant leap? (Score:5, Insightful)
Best way I can explain it as I understand it:
There are 1000 theories that explain mass. (I'm making up these numbers for demonstration purposes)
Given the data they released 900 can no longer be possible.
Of the remaining 100 theories, 90 require the higgs to provide that mass.
In the 10 that don't include the higgs as the provider of mass, there are large data sets that mostly rule them out.
For any of those 10 to work, there would have to be some pretty large coincidences.
Again, made up the numbers... but you get the idea.
It'd be like if someone stole your phone, and you found a guy with the same model phone and it's even got the same lock screen on it... and your password works on that phone. Are you 100% sure that's your phone? No... but you're pretty damned sure it is. Probably enough to punch him in the nose. :-)
Particle physics will now and forever be a game of probabilities. We'll never know 100%, but we'll know 99.99999999999999999999999999999% for sure.
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So, uh... How? (Score:1)
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As usual, the title is wrong! (Score:5, Insightful)
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IIRC most of mass comes from quantum electrodynamical interactions. About 5 per cent is due to Higgs field interactions.
Google: "youtube susskind higgs" for some lectures on higgs interactions and some implications of them. One of them is my source for this.
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I thought it was quantum chromodynamics mostly (the amount of energy holding quarks together is tremendous).
The "Hadron Masses" page [web.cern.ch] on CERN's "The Particle Adventure" site [web.cern.ch] agrees with you:
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Could one learn to control this field using mental training and gymnastics?
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Yes, there is a program run by a Professor Charles Xavier that can teach that.
Misleading title (Score:5, Informative)
Summary and title is a bit misleading. I was eager to see what they would say about how this 'higgs boson' infers mass to other particles, but they never say anything about that, they just talk about how they found this data and how they produced the results. Maybe I missed something?
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Re:Misleading title (Score:4, Informative)
Yeah, as usual, the summary is terrible. ALL collisions at the LHC are proton-proton collisions, not just the W-W ones.
What they're measuring is one of the higher-order corrections implied by the Higgs mechanism. Without the Higgs field, W bosons wouldn't have mass. Measuring how the Ws interact with each helps verify that the Higgs mechanism for explaining W boson mass is correct. Unfortunately, it's kinda hard to produce a W boson, much less two at once, much less getting them to interact with each other. You have to produce a lot of high-energy collisions to see it happen.
They did, and they got the answer they expected from the Higgs mechanism. Yay, Peter Higgs gets to keep his Nobel prize.
LHC (Score:4)
Everytime the LHC makes the news ... I think congratulations to the EU and then I think about the Superconducting Super Collider being built in Texas which was cancelled in 1993. We should have had these breakthroughs come out 15 years ago. In the United States. Thanks Congress for slowing down the pace of physics. Much appreciated .. NOT.
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Everytime the LHC makes the news ... I think congratulations to the EU and then I think about the Superconducting Super Collider being built in Texas which was cancelled in 1993. We should have had these breakthroughs come out 15 years ago. In the United States. Thanks Congress for slowing down the pace of physics. Much appreciated .. NOT.
ehhh ?
Given what has come out of the LHC it's been money well saved. I believe even with all the roadblocks and general BS that the government puts in the way of science and technology projects, the overall willingness to fund them and and total available funding is proportional to their return to society. Even in terms of employing physicists and maintaining our national capability to embark on cutting edge projects we would be far better off putting the money to next generation nuclear reactors/ alternati
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Even in terms of employing physicists and maintaining our national capability to embark on cutting edge projects we would be far better off putting the money to next generation nuclear reactors/ alternative fuel reactors like Thorium.
Wouldn't that tend to employ Nuclear Engineers rather than Particle Physicists?
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Here's an interesting link about the economic effects of publicly funded science: http://www.americanprogress.org/issues/technology/report/2012/12/10/47481/the-high-return-on-investment-for-publicly-funded-research/ [americanprogress.org]
However, science can take a while to pay off, so
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It's very difficult to predict which areas of science are likely to produce valuable discoveries. However, due to the incredible success of science throughout the last century (at least) it's quite a safe bet to invest in science and technoloy.
Here's an interesting link about the economic effects of publicly funded science: http://www.americanprogress.org/issues/technology/report/2012/12/10/47481/the-high-return-on-investment-for-publicly-funded-research/ [americanprogress.org]
That's a wonderful report let me ask you did you see what was missing in it ?
Think about it, what is needed for that report to be valid in a discussion of using public funds for science ?
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Did you get it ? Well if not you need to ask where are the baseline returns and just how much of those industrial returns have been recaptured. Just from your link we got "optical digital recording" I read that and see wow my tax dollars went to build china and japans DVD business. Look again at your same report, It's claiming "750 billion dollar return on the human genome project" that's flat out bullshit.
However, science can take a while to pay off, so at the moment, the LHC doesn't look good value, but who knows what we'll be up to in 50 years time?
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Why so depressed? Every pioneer who has every lived took on risks others were not willing to take. Not every pioneer succeeded, some failed, but it never meant that those who succeeded were wrong or that their efforts were of no value. Instead, we are grateful for what pioneers did. And you should be, too. Only because of pioneers who are pushing the limits further and who are giving us new knowledge do we also know what we are truly capable of.
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Not at all depressed. If the EU wants to fund vanity projects good on them. Having the U.S. not build the SSC was a pretty joyous moment, If we could only get NASA to not build expensive rockets that are horribly uneconomical like the upcoming SLS, and maybe farm that out to private companies that would be even better.
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No, you are not depressed any more, but why suddenly so jealous? Building carrier rockets is no cutting-edge science any more. Quantum physics is the new rocket science.
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Then again, it might have gone the way of the F35 Joint Strike Fighter project.
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> Everytime the LHC makes the news ... I think congratulations to the EU
For what? Collecting more useless statistics?
So far there has been zero actual scientific output from LHC. All we've done is confirm that a theory from the 1970s (and earlier) is still correct to our ability to test it. We haven't learned anything that we didn't think we already knew.
Call me when we get an anomalous result that *isn't* in the SM and then we're talking. Sadly, this article is an example of the opposite.
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You might think that the statistics are useless, but they're very useful to particle physicists.
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> We now have figures for the Higgs that have ruled out a large number of possible theories
Sure, until they modded the theories. I don't think any of the technicolors are REALLY gone yet?
> statistics are useless
"useless statistics" != "statistics are useless"
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Although there hasn't been any paradigm shifting science come out of the LHC, I wouldn't say there's been zero output. We now have figures for the Higgs that have ruled out a large number of possible theories. Before performing the experiments, no-one knew for sure what the results were going to be - we could easily have had surprising results that disagreed with the Standard Model.
I.e., paradigm-confirming science is also useful.
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but.. but... NUKLEAR!
Questionable Statistics: (Score:1)
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ATLAS "sees" trillions of collisions, but they can't possibly save the data from all of them, so they have algorithms that evaluate them quickly and save the 'interesting' ones, while tossing away the results from a large number of them. Thus "trillions" of collisions may only result in billions of "interesting" enough results to save.
That's not what this paper is about, at all (Score:4, Insightful)
"Researchers Find Evidence of How Higgs Particle Imparts Mass "
Ummm, no. This paper is about an unrelated bit of physics, W-W scattering. It is orthogonal to the Higgs mechanism.
Reading over the article I don't see any confusion on this point, so I'm looking at the author here on /.
Billions or Trillions (Score:2)
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They stacked the deck by channeling the proton streams at each other. (insert Ghostbusters reference)
It's the difference between the odds of getting into a traffic accident while driving to work vs. on a demolition derby track.