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posted by Fnord666 on Tuesday November 20 2018, @12:48PM   Printer-friendly
from the witty-comment-about-Illudium-PU-36-goes-here dept.

New Finding of Particle Physics may Help to Explain the Absence of Antimatter:

In the Standard Model of particle physics, there is almost no difference between matter and antimatter. But there is an abundance of evidence that our observable universe is made up only of matter -- if there was any antimatter, it would annihilate with nearby matter to produce very high intensity gamma radiation, which has not been observed. Therefore, figuring out how we ended up with an abundance of only matter is one of the biggest open questions in particle physics.

[...] About ten picoseconds after the Big Bang -- right about the time the Higgs boson was turning on -- the universe was a hot plasma of particles.

"The technique of dimensional reduction lets us replace the theory which describes this hot plasma with a simpler quantum theory with a set of rules that all the particles must follow," explains Dr. David Weir, the corresponding author of the article.

"It turns out that the heavier, slower-moving particles don't matter very much when these new rules are imposed, so we end up with a much less complicated theory."

This theory can then be studied with computer simulations, which provide a clear picture of what happened. In particular, they can tell us how violently out of equilibrium the universe was when the Higgs boson turned on. This is important for determining whether there was scope for producing the matter-antimatter asymmetry at this time in the history of the universe using the Two Higgs Doublet Model.

"Our results showed that it is indeed possible to explain the absence of antimatter and remain in agreement with existing observations," Dr. Weir remarks. Importantly, by making use of dimensional reduction, the new approach was completely independent of any previous work in this model.

Journal Reference:
Jens O. Andersen, Tyler Gorda, Andreas Helset, Lauri Niemi, Tuomas V. I. Tenkanen, Anders Tranberg, Aleksi Vuorinen, David J. Weir. Nonperturbative Analysis of the Electroweak Phase Transition in the Two Higgs Doublet Model. Physical Review Letters, 2018; 121 (19) DOI: 10.1103/PhysRevLett.121.191802


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  • (Score: 4, Informative) by Immerman on Tuesday November 20 2018, @06:46PM (5 children)

    by Immerman (3985) on Tuesday November 20 2018, @06:46PM (#764334)

    All the processes we know of for energy to condense into matter should create equal amounts of matter and antimatter- they're basically the exact same thing after all (according to current theories at least), just with opposite charges and the neat little quirk that they'll spontaneously self-annihilate back into energy if they come into contact with their opposite number.

    So yes, the screen you're reading this on IS antimatter, from the perspective of an antimatter-based physicist, who would reasonably consider own their matter "flavor" to be normal. However, the existence of such a physicist is extremely unlikely since, as far as we can tell, there's vanishingly little antimatter in the universe - even if it were dispersed uniformly in the vast voids of intergalactic space, it would annihilate the normal-matter particles expelled from the galaxies, and we'd see the resulting gamma-radiation "glow" across the entire sky.

    As for the fascination of the existence of antimatter, I'm sure it was fascinating when first conjectured and then discovered, but it's a natural outgrowth of quantum mechanics. If our theories of how normal matter is put together at the subatomic scale are correct, then antimatter must exist as well, and it *should* exist in equal amounts as normal matter.

    The modern theory of antimatter began in 1928, with a paper by Paul Dirac. Dirac realized that his relativistic version of the Schrödinger wave equation for electrons predicted the possibility of antielectrons

    https://en.wikipedia.org/wiki/Antimatter [wikipedia.org]

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  • (Score: 2) by legont on Wednesday November 21 2018, @01:57AM (4 children)

    by legont (4179) on Wednesday November 21 2018, @01:57AM (#764520)

    All the processes we know of for energy to condense into matter should create equal amounts of matter and antimatter- they're basically the exact same thing after all (according to current theories at least), just with opposite charges and the neat little quirk that they'll spontaneously self-annihilate back into energy if they come into contact with their opposite number.

    Are you saying that currently we can not produce any matter at all? We can not add even a single electron or something to the Universe? (because the corresponding antimatter particle will find something to annihilate with)

    --
    "Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
    • (Score: 2) by Immerman on Wednesday November 21 2018, @03:52AM (2 children)

      by Immerman (3985) on Wednesday November 21 2018, @03:52AM (#764570)

      Well, I couldn't tell you for sure, I'm not that much of an expert, but that would seem to be the gist. When we create matter and antimatter though it's in extremely artificial settings, so there may be some way to bias the outcome.

      If not though, then no, we couldn't create net matter, on average, at least not in the long term. I don't think we always create both at the same time, so you might turn a bunch of energy into an electron, and then you've added an electron to the universe. But if you tried to create a lot of electrons, we would expect half of them to actually be positrons. And sooner or later those positrons will contact an electron, and that matter will be converted back into energy.

      Which is why physicists are so puzzled by the existence of matter in the universe - it should have all annihilated with the antimatter and left only energy behind - energy that was then too diffuse to condense back into matter again, since the universe had expanded dramatically in the intervening moments.

      • (Score: 2) by legont on Wednesday November 21 2018, @04:38AM (1 child)

        by legont (4179) on Wednesday November 21 2018, @04:38AM (#764587)

        What if we dump the positron into a black hole? A little one created for this purpose; tiny enough to evaporate right away? Would this create a new electron long term?

        --
        "Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
        • (Score: 0) by Anonymous Coward on Wednesday November 21 2018, @05:27AM

          by Anonymous Coward on Wednesday November 21 2018, @05:27AM (#764599)

          It was just kugelblitz's (black holes formed by light) forming everywhere (since the light was so dense in the early universe) pulling in "random" (at least in the precise initial conditions will never be known sense) members of matter-antimatter pairs. The odds this would happen in exactly equal numbers is pretty much zero, so one of the two types was going to dominate, didnt matter which. I dunno why they cant figure this out. If the big bang concept is somewhat accurate that pretty much is guaranteed to have happened.

    • (Score: 1, Informative) by Anonymous Coward on Wednesday November 21 2018, @11:03AM

      by Anonymous Coward on Wednesday November 21 2018, @11:03AM (#764652)

      You can stop them annihilating by separating them. We've already made both matter and antimatter in colliders.