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Can anyone define anti-matter in concrete terms?

  1. Mar 31, 2012 #1
    Without using ' opposite charges of matter' explanation as a foundation for defining anti-matter, I wonder if anyone can present a more direct definition and examples.
     
  2. jcsd
  3. Mar 31, 2012 #2
    What troubles you about that explanation?
     
  4. Mar 31, 2012 #3

    mathman

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    Be careful about using opposite charge. Neutrons and other neutral particles have anti-particles (anti-neutrons, etc.).
     
  5. Mar 31, 2012 #4
    Its somewhat indirect. Its like defining a liability as the 'opposite' of an asset.
     
  6. Mar 31, 2012 #5
    A very good point indeed. That's is a valid reason to have something more direct as a description.
     
  7. Mar 31, 2012 #6

    sophiecentaur

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    I guess the main feature of an antiparticle is that it will combine with its corresponding particle so that they annihilate each other.
    When I first discovered that Anti matter did not involve Anti gravity, I was very disappointed!
     
  8. Mar 31, 2012 #7

    Bobbywhy

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    Last edited by a moderator: May 5, 2017
  9. Mar 31, 2012 #8
    Last edited by a moderator: May 5, 2017
  10. Mar 31, 2012 #9
    http://www.infoocean.info/avatar2.jpg [Broken]What troubles you about that explanation?
     
    Last edited by a moderator: May 5, 2017
  11. Mar 31, 2012 #10

    Nabeshin

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    Here's my problem with what you're saying about why you don't like the 'opposite' definition of antimatter. If you imagine WE had instead been made of antimatter, then the other stuff would be antimatter and you would be complaining you cannot explain that! It's like trying to define what an electron is without saying "Mass 511KeV, spin 1/2 and charge -1". That's WHAT it is. Similarly, what any particular antiparticle is is simply a list of all such numbers, but with charge reversed. (Note: Someone already pointed to the neutron, which is not the same as its antiparticle. This is of course because the neutron is not a fundamental particle, but rather composed of three quarks.) At this point I think it degenerates into the same discussion that was had here about what an electron REALLY is, which i'm sure you can find.
     
  12. Mar 31, 2012 #11
    I see your perspective yet I have a resistance to accept this 'pigeon hole' definition of anti-matter as if it came from the 'burning bush'
     
  13. Mar 31, 2012 #12
    I disagree, it ignores the theoretical construction that relates particles to each other. And saying the electron and the positron have the same mass, spin and opposite charge, does not tell you that upon contact they annihilate. So there is something more at work. A more illuminating answer might involve how theoretically antimatter can be deduced from matter, but I won't try to do that here as I'm not familiar enough with the material myself.
     
  14. Mar 31, 2012 #13

    K^2

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    That would be a really good argument. Except, neutrinos are neutral, and neutrino and anti-neutrino are not the same particle. So even for elementary particles, simply saying that difference between particle and anti-particle is charge is false.
     
  15. Mar 31, 2012 #14

    Nabeshin

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    I was under the impression the existence of majorana fermions was still an open question?
     
  16. Mar 31, 2012 #15

    Nabeshin

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    You might be right, but that's a different level of explanation. I guess someone could explain the difference in terms of solutions to Dirac's equation or some other similar mathematical solution... I don't know, maybe the OP will find such a discussion helpful? But I must admit you have a good point with annihilation, even in fully describing the properties of each particle one still needs to do some work explaining the relationship between them.
     
  17. Mar 31, 2012 #16
    I believe it still is, I read an article somewhere detailing an ongoing search to weed out their existence in neutrino collisions.
     
  18. Mar 31, 2012 #17

    K^2

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    Yes, but neutrino being such is extremely unlikely. There should be some experiments in the near future to determine it with better certainty, but the standard model assumes them to be Dirac fermions, and there seem to be no contradictions due to that. There are a whole bunch of weak interactions and decays whose cross-sections would be off if neutrinos were their own anti-particles.
     
  19. Apr 14, 2012 #18
    Well, an antimatter atom consists of neutrons and anti-protons in its nucleus, which, as its name suggests, are negatively charged protons. On the outside, they have positrons, which are positive electrons.
     
  20. Apr 15, 2012 #19
    Well. friend...

    Anti-matter is mainly defined in terms of something which when combined with matter will give rise to pure form of energy. I advice you to look at the LHC and the patterns of the productions when the particles of the matters are smashed. They anhilliate and combine to form pure energy. So,when you carefully observe pattern of the movement of particles taken at regular intervals of time. The show the way happening inside the matter when two proton particles are collided to liberate energy. According to Hypothesis, energy is only produced when matter and anti-matter combine. So, when they are smashed, there is pretty little amount of anti-matter produced which is liberated in the form of pure energy.

    So, here it indicates that mass, more precisely a particle, when excited to heavy energy and made into contact with other particles of similar energy and matter they are indeed producing anti-matter. Those antimatter particles when produced are living for very, and very little amount of time. It can be clearly observed from the patterns. So, Anti-matter according to me, is present everywhere in and around us. Energy is being produced and that energy is running through our entire body. So, Anti-matter is not something different or away. Its inside the matter itself. Try to understand the experiments made at CERN and LHC and you will clearly get to it..

    All the best...
     
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