Of Particular Significance

Off to CERN

POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON 11/10/2014

After a couple of months of hard work on grant writing, career plans and scientific research, I’ve made it back to my blogging keyboard.  I’m on my way to Switzerland for a couple of weeks in Europe, spending much of the time at the CERN laboratory. CERN, of course, is the host of the Large Hadron Collider [LHC], where the Higgs particle was discovered in 2012. I’ll be consulting with my experimentalist and theorist colleagues there… I have many questions for them. And I hope they’ll have many questions for me too, both ones I can answer and others that will force me to go off and think for a while.

You may recall that the LHC was turned off (as planned) in early 2013 for repairs and an upgrade. Run 2 of the LHC will start next year, with protons colliding at an energy of around 13 TeV per collision. This is larger than in Run 1, which saw 7 TeV per collision in 2011 and 8 TeV in 2012.  This increases the probability that a proton-proton collision will make a Higgs particle, which has a mass of 125 GeV/c², by about a factor of 2 ½.  (Don’t try to figure that out in your head; the calculation requires detailed knowledge of what’s inside a proton.) The number of proton-proton collisions per second will also be larger in Run 2 than in Run 1, though not immediately. In fact I would not be surprised if 2015 is mostly spent addressing unexpected challenges. But Run 1 was a classic: a small pilot run in 2010 led to rapid advances in 2011 and performance beyond expectations in 2012. It’s quite common for these machines to underperform at first, because of unforeseen issues, and outperform in the long run, as those issues are solved and human ingenuity has time to play a role. All of which is merely to say that I would view any really useful results in 2015 as a bonus; my focus is on 2016-2018.

Isn’t it a bit early to be thinking about 2016? No, now is the time to be thinking about 2016 triggering challenges for certain types of difficult-to-observe phenomena. These include exotic, unexpected decays of the Higgs particle, or other hard-to-observe types of Higgs particles that might exist and be lurking in the LHC’s data, or rare decays of the W and Z particle, and more generally, anything that involves a particle whose (rest) mass is in the 100 GeV/c² range, and whose mass-energy is therefore less than a percent of the overall proton-proton collision energy. The higher the collision energy grows, the harder it becomes to study relatively low-energy processes, even though we make more of them. To be able to examine them thoroughly and potentially discover something out of place — something that could reveal a secret worth even more than the Higgs particle itself — we have to become more and more clever, open-minded and vigilant.

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38 Responses

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  2. To everything CERN, CERN, CERN.
    There is a reason CERN, CERN, CERN.
    And a time for every particle under heaven.

  3. It is you that are missing the point: you mean to say “observer” instead of “vigilant”, but you are using the word “observant” instead of “observer”, which means something different from what you mean to say.

    Kind regards, GEN

  4. GEN

    My suggestion is to use observant instead of vigilant. I have not suggested to use the word observer instead of vigilant.
    I have tried to explain tto you why I prefer the word observant. So you know the reason why. I rest my case.

  5. I’m afraid that is not so, as somebody that “observes” is an “observer”, and not an “observant”.

    My “source” is the dictionary, which happens to be useful when it comes to the meanings and uses of the words.

    But I do not intend to be picky on the language, as english is not the mother tongue for anyone of us.

    Kind regards, GEN

  6. GEN

    Observant not only means to keep an eye on things, everybody can do that, but also putting the things one sees in perspective.

    A psychologist who is observing kids is not just keeping an eye on them.

    to comply to /to abide to as meaning of observant? what is your source?

  7. @martenvandijk: for those of us that are not native english speakers, we have to apy attention to the quirky way in which certain word with latin roots have a different meaning, as is the case of the meaning of the word “observant”: it means to “comply to” or to “abide to” and it does not mean “to keep an eye on events” … in fact, the word that Matt has used, “vigilant” is proper in conveying the meaning of “to keep an eye on things”.

    Kind regards, GEN

  8. Is there good reason to believe the 2016 onwards LHC data at the higher energy collisions will, credit or discreet supersymmetry?
    I mean if there was still no signs of SUSY partners at <11Tev to experimental LHC max energy per collision, would that be the end of SuperSymmetry been able to explain the vacuum energy catastropy and alike problems in cancellations?

    1. The LHC has already disproven several (Well more than jsut several.) SS theories. The problem is Supersymmetry theories are like people; if one fails you can’t really use that to discredit the group. (And if you do you’re kinda a jerk.) It’s quite possible the upcomming results will neatly home in on the one single right SS theory and all future textbooks will write about it as the experiment that finally validated SS and proved all doubters wrong.

      Or it’ll fall flat, that could happen too.

      1. Macro Dark Matter

        David M. Jacobs, Glenn D. Starkman
        (Submitted on 8 Oct 2014 (v1), last revised 13 Oct 2014 (this version, v2))
        Dark matter is a vital component of the current best model of our universe, ΛCDM. There are leading candidates for what the dark matter could be (e.g. weakly-interacting massive particles, or axions), but no compelling observational or experimental evidence exists to support these particular candidates, nor any beyond-the-Standard-Model physics that might produce such candidates. This suggests that other dark matter candidates, including ones that might arise in the Standard Model, should receive increased attention. Here we consider a general class of dark matter candidates with characteristic masses and interaction cross-sections characterized in units of grams and cm2, respectively — we therefore dub these macroscopic objects as Macros. Such dark matter candidates could potentially be assembled out of Standard Model particles (quarks and leptons) in the early universe. A combination of earth-based, astrophysical, and cosmological observations constrain a portion of the Macro parameter space; however a large region remains, most notably for nuclear-dense objects with masses in the range between about 50−1017g and 1020−1024g.
        It seems that my prediction is materializing

  9. Matt,
    What results from 2015 and beyond are you going to be most interested in? Where are you hoping we can see our first glimpses beyond the standard model?

  10. I guess that higher energy decays paths have more decay “segments” than lower energy decays paths, an some of those decay “segments” will include lower enery particles, so, it is hard to figure out what was the cause of those lower energy decay “segments”: did they appear of their own, or is it a part of the decay path of a higher enery particle?

  11. It’s good to hear back from you, Matt, and even more if you are visiting CERN again (we can only guess what interesting news you may bring from there).

    Regarding what you mentioned in this new post, when you say “The higher the collision energy grows, the harder it becomes to study relatively low-energy processes, even though we make more of them”, is it because with higher energy collisions, there are many more posibilities of types of decays happening, which make it more difficult to identify a certain kind of decay path from low enery particles?

    Kind regards, GEN

  12. Ok, a couple of physics questions;

    1. Is a black hole a spacetime region trapped below ZPE?

    2. Is this region “sucking up” high energy particles thru quantum tunnelling at very high rates (speeds)?

    1. Your questions seem to ask if black holes are low energy areas absorbing energy. This doesn’t make much sense as they would surely increase in energy and vanish. Like an icecube in a warm room they would only be able to absorb so much mass before ‘melting.’

      If something prevents this we have the problem of Hawking radiation; this removes energy from black holes, which would, in this scheme make them bigger, not smaller.

      There’s also the problem of what ‘below ZPE’ means; this would be a volume of space with lower energy than the bulk. ZPE is not some reservoir that can be tapped, it is the absolute lowest limit; it is in essence zero but not because nature likes wriggle room. Below ZPE would mean that actual ZPE is an illusion, a ‘false vacuum’ The black hole would expand, at light speed, converting the universe into its low energy state. (This is in fact a whole different theory, see ‘Will the Higgs destroy the universe?’)

      There are other issues too, but I think these suffice.

    1. There are a few things to keep in mind; firstly there’s not a lot of high speed stuff; you can use dust grains as units of measurement for it. Secondly they’re *so* high energy you’re not going to stop them or even slow them down much. Being hit by a stray particle wouldn’t do you any good, but it’s not instant death. The actual source of most injuries is the massive number of wires and pipes and sticky-out bits which have actually caused a number of injuries.

  13. We are all very enthusiastically awaiting for your seminar.

    Yes, there will be many questions for you… 🙂

    1. In reality , we can take the stand that no particles exist , what we see are phantoms since a particle will be transmutated to other particles so what we observe is a flux , a flowing river where in every second new water comes , old water goes while the “”River “” remains , so are particles .. flowing like water but what remain is permanently fixed , permanent are the rules not the particles , physics teach that the proton is a fixed entity , but the same fixed proton is never a fixed entity , it is always changing — not decaying — and this grand lesson I learned thru the long time reflections on what Matt. teach in every single post ……..thanks our great teacher .

  14. Say, if I wanted to plan a trip to CERN, what may I know besides what their webpage would tell me? How about travel tips? Local creature comforts? Other megaliths?

  15. So thrilling to have you back on the blog!!!
    Yes, I also heard about the Higgs maybe not being a Higgs. What are the chances for this? What does it mean?

    “Last year CERN announced the finding of a new elementary particle, the Higgs particle. But maybe it wasn’t the Higgs particle, maybe it just looks like it. And maybe it is not alone.
    Many calculations indicate that the particle discovered last year in the CERN particle accelerator was indeed the famous Higgs particle. Physicists agree that the CERN experiments did find a new particle that had never been seen before, but according to an international research team, there is no conclusive evidence that the particle was indeed the Higgs particle.
    The research team has scrutinized the existing scientific data from CERN about the newfound particle and published their analysis in the journal Physical Review D. A member of this team is Mads Toudal Frandsen, associate professor at the Center for Cosmology and Particle Physics Phenomenology, Department of Physics, Chemistry and Pharmacy at the University of Southern Denmark.
    “The CERN data is generally taken as evidence that the particle is the Higgs particle. It is true that the Higgs particle can explain the data but there can be other explanations, we would also get this data from other particles”, Mads Toudal Frandsen explains.
    The researchers’ analysis does not debunk the possibility that CERN has discovered the Higgs particle. That is still possible – but it is equally possible that it is a different kind of particle.
    “The current data is not precise enough to determine exactly what the particle is. It could be a number of other known particles”, says Mads Toudal Frandsen.
    But if it wasn’t the Higgs particle, that was found in CERN’s particle accelerator, then what was it?
    “We believe that it may be a so-called techni-higgs particle. This particle is in some ways similar to the Higgs particle – hence half of the name”, says Mads Toudal Frandsen.
    Although the techni-higgs particle and Higgs particle can easily be confused in experiments, they are two very different particles belonging to two very different theories of how the universe was created.
    The Higgs particle is the missing piece in the theory called the Standard Model. This theory describes three of the four forces of nature. But it does not explain what dark matter is – the substance that makes up most of the universe. A techni-higgs particle, if it exists, is a completely different thing:
    “A techni-higgs particle is not an elementary particle. Instead, it consists of so-called techni-quarks, which we believe are elementary. Techni-quarks may bind together in various ways to form for instance techni-higgs particles, while other combinations may form dark matter. We therefore expect to find several different particles at the LHC, all built by techni-quarks”, says Mads Toudal Frandsen.
    If techni-quarks exist, there must be a force to bind them together so that they can form particles. None of the four known forces of nature (gravity, the electromagnetic force, the weak nuclear force and the strong nuclear force) are any good at binding techni-quarks together. There must therefore be a yet undiscovered force of nature. This force is called the the technicolor force.
    What was found last year in CERN’s accelerator could thus be either the Higgs particle of the Standard Model or a light techni-higgs particle, composed of two techni-quarks.
    Mads Toudal Frandsen believes that more data from CERN will probably be able to determine if it was a Higgs or a techni-higgs particle. If CERN gets an even more powerful accelerator, it will in principle be able to observe techni-quarks directly.
    More information: Technicolor Higgs boson in the light of LHC data. Phys. Rev. D 90, 035012th Alexander Belyaev, Matthew S. Brown, Roshan Foadi, and Mads T. Frandsen. journals.aps.org/prd/abstract/… 3/PhysRevD.90.035012 . On Arxiv: arxiv.org/abs/1309.2097

    1. I also heard about the Higgs maybe not being a Higgs… What does it mean?

      For the most part this is a semantic issue, a matter of terminology.

      The story you share suggests that the Higgs particle discovered in 2012, while still a Higgs particle, may not necessarily be the simplest possible (“standard model”) Higgs particle. Instead it may be some more complicated type of Higgs particle, which this story calls a “techni-Higgs” particle.

      Matt has discussed the semantics of a Higgs particle, as opposed to the simplest possible (“standard model”) Higgs particle in several posts in the past, including

      Since there have probably been thousands of articles over the past three decades or so considering possibilities of this sort, I find it odd that this article in particular is suddenly receiving so much attention, roughly 14 months after it was written. If you care about the details, the main argument in this article is that this “techni-Higgs” particle (the more complicated possibility) may behave much more like the standard model Higgs (the simplest possibility) than is generally believed. Therefore, since the Higgs results from the LHC so far are consistent with the simplest possibility (the standard model Higgs), they can also be consistent with the more complicated possibility (the “techni-Higgs”).

    2. Hi Margot: Such controversies in science have been going on for hundreds of years. By and large, this is normal and healthy process for science. Eventually the best and correct ideas win .The big difference these days is that the news articles are written by journalists who themselves are not scientists. And the human instinct is to be first in announcing sensational news and get credit for that. They often exaggerate and are frequently wrong! That does confuse laymen who might think that scientists change their mind every day!! IMHO this particular one is unlikely to be right. But I could be wrong of course.

  16. I have a burning question I hope that you can answer. In his book, Beyond the God Particle, Ledeman says the proton proton collisions provide the energy to “hit” space really hard to “break” loose particles from fields(such as the HIggs field) that exist in space. I got the impression it is not the resulting particles from the make up of the protons after collision that we are seeing or want to see, rather the partilces that are associated with the fields in the vacuum of space. Is this a correct picture of what is really happening, becasue a Higg’s particle is a disturbance in the Higgs field not a component of a proton.

    1. Not to preempt Matt, but Lederman’s account sounds like a slightly better metaphor than the usual one, as long as you remember it’s still a metaphor. 😉

      Indeed, the Higgs particle isn’t a component of a proton, so one way to think about why proton collisions can produce Higgs particles is to phrase it as “hitting” space and “breaking loose” particles from preexisting fields.

      That’s still a metaphor, though. The thing is, even if you’re producing something that is “inside” a proton by colliding two protons, the process can be physically the same as when you’re producing something that’s not “inside” the protons, like the Higgs. So it’s kind of a false distinction.

      Instead, I like to emphasize that the fundamental forces don’t just move particles around, they can change one particle into another. You can see that with beta decay, where the weak nuclear force changes a neutron into a proton plus an electron plus a neutrino. In general, all of the fundamental forces have the ability to change one type of particle into another, provided that everything is properly conserved.

  17. Welllcome back Matt . …..guess what !? there are as you for sure know some talks about the Higgs being not a Higgs after all !! Lot of talks also about techni- quarks making a smaller higgs …..
    I got tired waiting for you to clarify all of that …..would you ??
    I only trust your word Matt.

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