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B Is Dark Matter physics low or high energy physics?

  1. May 6, 2017 #1
    Is dark matter physics considered a low or high energy physics, and why?
     
  2. jcsd
  3. May 6, 2017 #2

    phinds

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    What do you think and why?
     
  4. May 6, 2017 #3
    Beyond the standard models seem to involve high energy like what goes on in the electroweak or GUT sector or QG planck sector. It sounds like they have already fully explored the low energy regime.. but isn't dark matter a low energy sector, or high? I'm not sure.
     
  5. May 6, 2017 #4
    Last edited: May 6, 2017
  6. May 6, 2017 #5
    Is low energy physics not the same meaning as weak scale physics.

    Weak-scale physics occur at GeV or below TeV. So I guess dark matter physics is a weak-scale or low energy physics?
     
  7. May 7, 2017 #6
    The reason I'm not sure if dark energy falls under weak scale (low energy) or high energy physics is due to the concept of the so called dark sector portal that gives mass to the Higgs sector to solve the Hierarchy Problem. So is dark energy a low energy (weak scale?) or high energy physics?
     
  8. May 7, 2017 #7

    kimbyd

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    The production of dark matter particles is potentially possible in high energy experiments. Other attempts to directly detect these particles involve nuclear interactions. So this means that the detection of dark matter particles requires use of many of the tools of high energy physics.

    Furthermore, the theories of how these particles might have been produced in the early universe involve high energy physics.
     
  9. May 7, 2017 #8
    There is a subforum called High Energy, Nuclear and Particle Physics.

    What falls under Low Energy Physics then?

    Is Low Energy Physics the same as Weak-Scale Physics?
     
  10. May 7, 2017 #9
    There is no "Low Energy Physics".

    "High Energy Physics" is actually a misnomer, originating from the time when ~1GeV energies were considered big for a single particle. In fact, High Energy Physics means "smallest scale physics", a branch of physics which studies elementary particles.
     
  11. May 7, 2017 #10
    Oh. I thought High Energy Physics dealed with at least 1 TeV and higher while Low Energy Physics deals with the GeV.
    What is it called then for those 1 TeV or above... "Really High Energy Physics"?

    What about Weak-scale physics? What is Weak-scale physics compared to this "High Energy Physics" to "Really High Energy Physics"?
     
  12. May 7, 2017 #11
    It's all "High Energy Physics".
    One step lower from it is chemistry.
     
  13. May 7, 2017 #12
    No wonder only a few post at the High Nuclear subforum because it makes one imagine quark-gluon soup or higgs field.. maybe it should be renamed "Normal Energy Physics..."

    But for GUT or planck scale energy physics.. there should be a name for it to distinguish from below it.

    For instance. How could I state the sentence that "Before physicists focus on GUT or planck scale physics".. they should first explore all the GeV sector because there may be other surprises still awaiting there".. or maybe this is the right sentence?

    What GeV or MeV is chemistry?
     
  14. May 8, 2017 #13
    I think you are mistaken. See this thread of the conversations between seasoned Science Advisors: https://www.physicsforums.com/threads/new-experiments-supporting-bohmian-mechanics.913098/page-2 message 27 & 28

    vanhees71: Of course, the theory breaks down at very high energies, when you come close to the Landau pole, but you are in the realm of relativistic physics at much lower energy scales than that.

    atyy: If the theory breaks down at high energies, then we can consider the possibilty that the low energy relativistic theory - including the Lamb shift - emerges from a non-relativistic high energy theory.

    nikkkom... if the words "low energy" doesn't exist.. why would they use them? Or maybe there are two meanings of "High Energy".. one about scales where closer to the Landau pole would be High Energy. The other meaning would be the accelerator energies? Are you referring only to the latter? please clarity, and others too. Thanks!
     
  15. May 8, 2017 #14

    kimbyd

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    I don't see how this discussion applies to the topic at hand. It's a pretty speculative discussion about what might lie beyond the standard model.

    As far as we know, our current model of high-energy physics is exceedingly accurate everywhere (except for systems where self-gravity is a significant component). Relativistic physics reduces to non-relativistic physics in the appropriate limit. Quantum physics reduces to classical physics in the appropriate limit. The standard model is the most accurate theory of the behavior of small things that we have at present. Its application to larger systems (but not large enough for self-gravity to be important) is only really limited by the excessive computational difficulty of applying the theory.
     
  16. May 8, 2017 #15
    Here's how its relevant.

    According to nikkkom.. High Energy Physics encompass even the low GeV to TeV and he said there is no such thing as "Low Energy"...

    While in the science advisors context. High Energy is near the Landau Pole and Low Energy are much lower than it.

    If I'll communicate to the public in article or book. Who must I follow and what is the mainstream view?
     
  17. May 8, 2017 #16

    kimbyd

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    The standard model of high-energy physics is the most accurate model we have, and so far as we know is accurate in all experiments ever done under any situation that didn't involve self-gravity.

    All other models can be thought of as simplified versions. The standard model is very, very accurate, but it's also very hard to use. When the details of the standard model aren't necessary for the system at hand, it's better to use a simpler model, such as the non-relativistic Schroedinger's Equation. Or, if quantum mechanics doesn't matter, Newton's Laws.

    The only real conflict between different models of physics is between General Relativity and quantum mechanics. This isn't a low-energy/high-energy distinction.
     
  18. May 8, 2017 #17
    You still can't understand my questions. Let me illustrate it by means of definition...

    for vanhees and atyy,

    High Energy = small size near the landau pole (is landau pole near the GUT or planck scale?)
    Low Energy = large size below the landau pole (or below the GUT or planck scale)?

    for nikkkom

    High Energy = everything from small size to large size (?)

    If i'll write an article.. which should I follow.. what is the mainstream physicists use of it?
     
  19. May 8, 2017 #18

    PeterDonis

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    We can't answer that question here. The terms "high energy physics" and "low energy physics" don't have standard definitions. You can define them however you like, as long as you make your definitions clear. In other words, this thread appears to be about terminology, not physics.

    Which leads to the obvious next question: do you have a question about physics?
     
  20. May 8, 2017 #19
    I guess I'll use vanhees and atyy definitions where
    High Energy = small size small wavelength high energy scale (but what TeV does this start?)
    Low Energy = big size big wavelength low energy

    nikkkom definition is useless because you can't describe any distinction because all are High Energy (from 1 GeV) for him.

    The thread title is the question.. Is Dark Matter physics low or high energy physics? Or more clearly.

    Is Dark Matter physics big size big wavelength low energy physics or is it small size small wavelength high energy physics?
    or what MeV, GeV, or TeV are the scale of dark matter?
     
  21. May 8, 2017 #20

    PeterDonis

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    That's a question about terminology, not physics.

    That's a question about physics. The short answer is that we don't know because we don't know what dark matter is. All we know is that it's not one of the Standard Model particles.

    A longer answer requires getting more specific about what this "energy scale" actually means. There are at least two factors involved: the mass of the particle, and the strength of the interactions it has with other particles. For example, photons are massless, and they're easy to detect because they are involved in the electromagnetic interaction, which is strong enough that it has all sorts of observable effects in experiments even at room temperature. The weak gauge bosons are quite massive as elementary particles go, plus their interactions are not as strong as EM, so you need to run pretty high energy experiments to detect them, at least directly. (Note that there was considerable indirect evidence for them from lower energy experiments well before they were directly detected.) But neutrinos, for example, are very light (we know now they're not massless, but their masses are very small as elementary particle masses go), but they're still hard to detect because they interact so weakly with anything else. The interactions themselves are not very high energy--you don't need a particle accelerator to detect neutrinos (the Kamiokande experiments for detecting solar neutrinos are just large tanks of liquid at more or less room temperature)--but they're so weak that they happen very rarely.

    The problem with dark matter is that we don't know which of the last two reasons (large mass or very weak interactions) is the reason we haven't directly detected particles that match its properties. Is it because they are very massive particles (for example, supersymmetric partners of one or more of the Standard Model particles)? Or is it because they're so weakly interacting (for example, very small mass like neutrinos plus no interactions other than gravity)? We don't know.
     
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