Physicists believe that an unknown force could be acting on sub-atomic particles known as muons.
  • Skyler@kbin.social
    384·
    1 year ago

    Have you all not seen Interstellar? Obviously the fifth force of nature is love.

  • palordrolap@kbin.social
    19·
    1 year ago

    What are the odds that muons are more sensitive to neutrino interaction and this is what the scientists are seeing? Muons are pretty massive, after all, and neutrinos are literally everywhere. Obligatory: “billions of neutrinos pass through you every second”.

    Muons are leptons like neutrinos and their electron cousins, and we already know that electrons can be boosted by the occasional neutrino interaction. A free muon in a magnetic field has nowhere to be boosted to, so, coupled with a hypothetically higher chance of interacting with a neutrino, I’d expect something to happen when it does, though not exactly what.

    I figure we don’t already use muons in neutrino detectors because they don’t last very long (about a second) before decaying, and the only way to get them to last longer is to accelerate them to a decent fraction of the speed of light. That way, from our reference frame they can last minutes or more. That’s going to be energy-hungry compared to the passive detectors we have.

    i.e. the passive detectors which take advantage of the aforementioned electron / atom interaction.

  • Ashyr@sh.itjust.worksEnglish
    8·
    1 year ago

    Interesting. I never expected a fifth. If anything, I’ve seen a push for reducing the number down to three (gravity, strong and electro-weak) or possibly just two.

  • 133arc585@lemmy.ml
    41·
    1 year ago

    Tangentially related but I can’t seem to find the answers and I have a couple questions that perhaps someone can answer:

    1. Do stars actually generate muons directly? From what I understand the muons on Earth are a result of cosmic rays colliding wtih particles in the atmosphere.
    2. If they do, how far do they travel before decaying? Even if they travel at relativistic speeds, they have a mean lifetime of 2.2 ns, so the math seems to say they don’t travel very far at all on average.
    3. Either way, are there any other sources of muons in the universe? I’m curious what the muon density distribution in the universe would look like.
    • SeventyTwoTrillion [he/him]@hexbear.netEnglish
      2·
      1 year ago

      Do stars actually generate muons directly? From what I understand the muons on Earth are a result of cosmic rays colliding wtih particles in the atmosphere.

      Muons are naturally generated by cosmic ray protons colliding with atmospheric molecules and creating pions, which then rapidly decay to muons and muon neutrinos. These themselves then decay into a bunch of other things.

      If they do, how far do they travel before decaying? Even if they travel at relativistic speeds, they have a mean lifetime of 2.2 ns, so the math seems to say they don’t travel very far at all on average.

      That muons can hit the Earth is one of the key pieces of evidence in favor of relativity, in fact. As you say, with a mean lifetime of 2.2 nanoseconds, they shouldn’t be able to hit the surface of the Earth, but because at relativistic speeds time dilation occurs from our frame of reference (or, equivalently, in the muon’s inertial frame, it sees the distance it has to travel be radically shortened via length contraction), they do end up hitting the earth.

      Either way, are there any other sources of muons in the universe? I’m curious what the muon density distribution in the universe would look like.

      I doubt it, because they decay so quickly. AFAIK you have to do it via the pion decay route, and all the muons we create are in particle accelerators. I guess it would be like how we create radioactive isotopes in hospitals on-demand for medical purposes that wouldn’t survive transportation to the hospital before decay, and couldn’t be stored long-term because, well, they would decay.

      as an aside, Nature is rather more pessimistic about the discovery, which I think is reasonable.

      • 133arc585@lemmy.ml
        21·
        1 year ago

        Muons are naturally generated by cosmic ray protons colliding with atmospheric molecules and creating pions, which then rapidly decay to muons and muon neutrinos.

        So in theory they could exist anywhere in the universe somewhat close to a star, if the relevant particles in our atmosphere are around that star? That’s what I meant about the density distribution: are they spherically distributed around (all) stars, or are they only present in very specific situations?

        These themselves then decay into a bunch of other things.

        I thought they had a small selection of possible decay products. Not particularly relevant to me at the moment, though.

        As you say, with a mean lifetime of 2.2 nanoseconds, they shouldn’t be able to hit the surface of the Earth, but because at relativistic speeds time dilation occurs from our frame of reference (or, equivalently, in the muon’s inertial frame, it sees the distance it has to travel be radically shortened via length contraction), they do end up hitting the earth.

        I mistyped the mean lifetime, it’s actually 2.2 microseconds. That’s three orders of magnitude different, but from a (non-relativistic) view it would still only travel about 66 centimeters. I’m missing too much information to try to solve the length contraction equation (I don’t know its length, or its velocity) for the observed length. I’m curious here because they’re able to travel on the order of roughly 50 meters into the Earth, and from what I can find they disappear there due to absorption from the many atoms they pass through on that path. So that leads me to a question: If there is not relatively dense earth to get in the way and attenuate the muon, such as if it were produced by a gas cloud beside a star, how far would it realistically be able to travel? Since the muons on Earth “die” from absorption rather than lasting long enough to decay via weak force, they would, in open space, surely be able to travel far enough without enough collisions such that they do end up “dying” by decay.

        Thanks for the reply, I am curious here about something that I don’t have enough knowledge to answer for myself.

  • Lenguador@kbin.social
    31·
    1 year ago

    From Wikipedia: this is only a 1-sigma result compared to theory using lattice calculations. It would have been 5.1-sigma if the calculation method had not been improved.
    Many calculations in the standard model are mathematically intractable with current methods, so improving approximate solutions is not trivial and not surprising that we’ve found improvements.

    • slackassassin@sh.itjust.works
      2·
      1 year ago

      So what? I mean, not to be shitty, but this is important work that allows for this downplayed and pedantic take to even exist.

      Experimental verifications should be celebrated, and the fact that they’re not is the problem with the current state of science journalism.

    • 133arc585@lemmy.ml
      381·
      1 year ago
      1. Strong nuclear force: holds the nucleus of an atom together
      2. Weak nuclear force: responsible for radioactive decay
      3. Electromagnetic force: of charged particles
      4. Gravitational force: attractive force between objects with mass
      • CanadaPlus@lemmy.sdf.org
        82·
        1 year ago

        Not all decays are weak-based, though, and not all weak phenomina are directly related to radioactivity. That’s just the only thing a layman has heard of where it’s relevant.

        The strong force only holds atoms together through a sort of trickle-down force, too, but that one feels like splitting hairs.

        • 133arc585@lemmy.ml
          201·
          1 year ago

          The person I replied to wasn’t able to name the forces beyond gravity, so I think over-simplification and reduction to specific phenomena they would have heard of is appropriate.

          • CanadaPlus@lemmy.sdf.org
            62·
            1 year ago

            Oh, absolutely. I was adding on for anyone else reading who might appreciate answer gravy. Sorry if it came across as critical of what you wrote, my bad.

      • Knusper@feddit.de
        5·
        1 year ago

        Well, the article currently lists them as: gravity, electromagnetism, the strong force and the weak force.

        If you’re not familiar, you wouldn’t be able to guess that the last two are nuclear forces and in the context of a new force, that list is rather confusing.