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Researchers Find Evidence of How Higgs Particle Imparts Mass 91

Posted by Unknown Lamer
from the type-13-planet dept.
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.
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Researchers Find Evidence of How Higgs Particle Imparts Mass

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  • Re:So, uh... How? (Score:3, Informative)

    by bswarm (2540294) on Wednesday July 16, 2014 @02:05PM (#47468505)
  • Misleading title (Score:5, Informative)

    by duke_cheetah2003 (862933) on Wednesday July 16, 2014 @02:06PM (#47468515) Homepage

    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?

  • Re:Erm (Score:5, Informative)

    by azav (469988) on Wednesday July 16, 2014 @02:29PM (#47468767) Homepage Journal
    "Now finalized based on a total of 34 observed events, the measured interaction rate is in good agreement with that predicted by the Standard Model, a theory describing all known fundamental particles and their interactions."

    "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." "
  • Re:Erm (Score:5, Informative)

    by Lord Crc (151920) on Wednesday July 16, 2014 @02:31PM (#47468791)

    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.

  • by Anonymous Coward on Wednesday July 16, 2014 @02:35PM (#47468825)
    Parent is modded up a lot for not saying much... Einstein's equations just say that mass is just a type of energy and allow for that to be changed into other kinds of energy. Beyond explaining how binding energy factors into the mass of things made of multiple parts, it doesn't say anything about the source of rest mass of elementary particles. As far as knowing pretty soon some theory of mass, this doesn't change that, it confirms a theory that has been around for some time. As far as simplifying the equations involved, I'm willing to bet any further theories that explain more than current ones aren't going to be much simpler, especially when you compared quantum field theory that underlies the Higgs mechanism with vanilla quantum mechanics.
  • Re:Misleading title (Score:4, Informative)

    by jfengel (409917) on Wednesday July 16, 2014 @05:35PM (#47470565) Homepage Journal

    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.

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