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Unexpected LHC Results Summary

  1. Nov 26, 2013 #1


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    Is there a list for all unexpected LHC results from the start of operation that cant be explained by the standard model? Two years ago I remembered a result where they encountered unexpected macroscopic superposition akin to superconductivity.. where the particles dance together... anyone remember it? how do they explain it? Please share all weird results from the beginning of operation.
  2. jcsd
  3. Nov 26, 2013 #2

    Vanadium 50

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    Yes, and here is that list:
  4. Nov 26, 2013 #3


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    You forgot to include the link.
  5. Nov 26, 2013 #4


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    He actually wrote down the list, Kye.
  6. Nov 26, 2013 #5


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    Maybe you saw it in your PF external software, but it didn't appear in the public site see message # 2 https://www.physicsforums.com/showthread.php?t=725134

    The LHC will be online 2015 and we will miss it for 2 years so it's good to check the complete unexpected things it has discovered..
  7. Nov 26, 2013 #6

    George Jones

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    i.e, the list is the empty set, since the LHC has (yet) to produce any unexpected results.
  8. Nov 26, 2013 #7


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    Staff: Mentor

  9. Nov 26, 2013 #8


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    I read an LHC result in the news about two years ago where the showers of particles have macroscopic coherence.. and they are surprised about it.. if anyone has encountered it, please share it.. i'll look for old archives...
  10. Nov 26, 2013 #9


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    :bugeye: You cracked a joke!?
  11. Nov 26, 2013 #10


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    I found it after 40 minutes of searching at google. What do you guys think of the above?

    ""Physicists conducting experiments on the world's largest atom smasher
    have discovered a new phenomenon in proton interactions that may change
    our view of the Standard Model of particle physics.

    A study of "high multiplicity" collisions, where a hundred or more
    charged particles are produced, has revealed indications that some
    particles are somehow "correlated" or associated together when they were
    created at the point of collision."
  12. Nov 27, 2013 #11


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    That article is short on details, so we can't be sure what is actually being referred to. But correlations between particles produced at a collider are by no means a sign of new physics. Whenever we have conservation laws (momentum, angular momentum, charge, etc), there will be correlations between the final state particles corresponding to the conservation of these quantities. As a simple example, suppose we collide an electron of momentum ##\vec{p}## with a positron with momentum ##-\vec{p}## to produce a proton and an antiproton. If we measure the proton to have momentum ##\vec{k}##, then momentum conservation dictates that the antiproton has momentum ##-\vec{k}##. In the language of quantum mechanics we can describe these correlations using entangled states if we want to.

    From googling the physicist Vladimir Gavrilov referred to in the article, I suspect that he is referring to something called color coherence. This is something that is theoretically predicted and described in standard references like this one.
  13. Nov 27, 2013 #12


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    why did the article mentioned this?

    ""This is a phenomenon that has not been predicted by theoretical calculations," Gavrilov said."

    maybe the "not" is a typo or maybe the russian physicist didnt know the meaning of color coherence? or maybe the article misreporting. hope other russians can shed light on this
    Last edited by a moderator: Nov 27, 2013
  14. Nov 27, 2013 #13


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    Maybe http://cms.web.cern.ch/news/new-two-particle-correlations-observed-cms-detector-lhc ?
    "The CMS Collaboration at CERN released today a paper entitled "Observation of Long-Range Near-Side Angular Correlations in Proton-Proton Collisions" that details signs of a new phenomenon in proton interactions."

    "However, what is novel about the ridge in high multiplicity pp is that particles are produced in a correlated fashion not only over long range in rapidity but also collimated in azimuthal angle (near-side). This peculiar new feature was not observed before in pp or ppbar, or any theoretical modelings of pp collisions. The microscopic dynamics of high multiplicity particle production and near-side ridge correlations in pp have not been fully understood yet."

    "While in the meantime far eclipsed by the discovery of ’a Higgs-like particle’, this ’near side ridge’ is arguably still the most unexpected LHC discovery to date and spawned a large variety of different explanations, from mildly speculative to outright weird [48]. The most serious contenders are saturation physics, as formulated in the Color Glass Condensate model (CGC), and collective hydrodynamic flow."
    Last edited: Nov 27, 2013
  15. Nov 27, 2013 #14


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    Thanks for the links. I spent several hours reading and analyzing them and finally understood what's it saying after checking many links (recommended for newbies those who want to get the essence of it all) especially:



    "Somehow they fly at the same direction even though it's not clear how they can communicate their direction with one another. That has surprised many people, including us," MIT physicist Gunther Roland, whose group led the analysis of the collision data along with Wei Liof Rice University, said in a statement.

    A similar flight pattern is seen when two heavy particles, such as lead and lead, crash into each other. In this case, the collisions create what's called quark-gluon plasma — a superhot soup of particles similar to the state of the universe just after the Big Bang. This soup can sweep particles in the same direction, explaining why their flight directions would be correlated.

    But quark-gluon plasma isn't possible with lead-proton collisions, like the ones in the new study. Now researchers think a different state of matter, the color-glass condensate, may act in a similar way. The color-glass condensate's dense swarm of gluons may also sweep particles off in the same direction, suggested Brookhaven National Laboratory physicistRajuVenugopalan, who first predicted the substance, which may also be seen after proton-proton collisions."


    So maybe color-glass condensate is the answer? For those who still think about entanglement, just imagine the particles not moving away from each other with correlations in the spin or momentum, but in direction which is not possible if just pure quantum (?) that's why they have to propose new state of matter of even collective hydrodynamic flow (what is the ramification of this?). If it's just plain color-glass condensate, would this change anything in search of new physics beyond the standard model or just nothing?
  16. Nov 29, 2013 #15
    Anything to do with heavy ions should keep in mind the difference between new "fundamental" physics, and new physics at the level of QCD with a condensed matter flavour. QCD interactions with that many particles is pushing the theory into less well-studied phases, and one should not be too surprised that new phenomenon emerge which require more theoretical study. However, this is going to be confined within the existing framework of the Standard Model, rather than pointing at some fundamental violation of it.
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