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Why is Annihilation Not a Force?

  1. Jun 16, 2011 #1
    If no other force is responsible for annihilation, is it a force in itself? Does one always need a gauge boson in order to have a force? If so, can one consider that matter and antimatter are their own gauge bosons with annihilation?

  2. jcsd
  3. Jun 16, 2011 #2
    How can annihilation, which is some event, be a force?
  4. Jun 16, 2011 #3
    Can events arise that are not the result of a force?

  5. Jun 16, 2011 #4
    Well, if you assume that two particles are approaching eachother at certain velocities, for example an electron and a photon, they would collide. But not because of any kind of attraction, but because their trajectories simply crossed.
  6. Jun 16, 2011 #5
    I see; what is annihilation in that case? Can it be conceived as a selective and collective very high-energy decay? I'm having trouble understanding the concept itself...

  7. Jun 16, 2011 #6
    I must admit that I'm not sure either. Maybe somebody else could provide some insights.
  8. Jun 16, 2011 #7
    if a particle and a anti- particle annihilate each other a gauge boson is realized. The rest mass of these two particles is converted into the energy of the gauge boson. Annihilation is a particular type of interaction that is generated by a force.
  9. Jun 16, 2011 #8
    It is caused by a force, yes. But the process that happens at the very moment of the annihilation? Is it correct to say that this is part of the force as well?
  10. Jun 16, 2011 #9


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    Saying annihilation is a force is like saying beta decay is a force. It is not. It is an event caused by interactions of forces.
  11. Jun 16, 2011 #10


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    I don't believe so. A force is:
    In physics, a force is any influence that causes a free body to undergo a change in speed, a change in direction, or a change in shape.

    The electromagnetic force causes the attraction between anti particles which leads to annihilation. The annihilation itself uses forces to convert the particles into other particles.
  12. Jun 16, 2011 #11
    pls learn some quantum fied theory to understand these things better.
    the question of annhilation requires some simple qft.
  13. Jun 21, 2011 #12
    So to summarise, a particle and its anti-particle are drawn together by the electromagnetic force and then annihilate themselves via other forces by the total conversion of mass into boatloads of massless gauge bosons. In that case the 'other forces' must be the strong force since weak force gauge bosons have mass.

    Is this correct? And what about a neutrino + anti-neutrino annihilation? Surely they are not drawn together by the electromagnetic force...

  14. Jun 21, 2011 #13
    All the 4 forces in nature have an atraction, so the particles can all be drawn together by it, or just happend to collide by accident (or on purpose in colliders).

    And also massive gauge bosons can also be created, because it's a conversion into energy and that becomes gauge bosons and other particles. If no massive gauge bosons could be formed, they wouldn't have discovered the W's en Z boson.
  15. Jun 23, 2011 #14


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    The mysterious process of magnetic reconnection annihilation may be one of the most important and ubiquitous processes in nature.

    During the proposed annihilation process which creates the giant magnetic bubbles at our heliosheath, cosmic rays may be either blocked, created or both.
    http://www.planetary.org/news/2011/0612_Voyager_Discovers_Possible_Sea_of_Huge.html [Broken]

    Respectfully submitted,
    Last edited by a moderator: May 5, 2017
  16. Jun 23, 2011 #15


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    I'm not sure honestly.
  17. Jun 24, 2011 #16
    OK, I guess what I am trying to understand is whether annihilation is:

    - Simply a nominal high-energy particle collision, except that it takes place between a particle and its anti-particle; or

    - A very special type of high-energy particle collision where i) any and all particle mass is transformed 100% into non-massive high-energy particles streams and ii) the collision mechanism is different from normal high-energy collisions and/or is unique.

    It's simply this thing that one keeps reading that annihilation converts both your particles into pure energy. Is it really accurate to say such a thing? In terms of %, how much mass is typically converted into massless gauge bosons in annihilation?

  18. Jun 24, 2011 #17


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    It doesn't have to be a high energy collision.
    Also, depending on the particles that are annihilating you can have many different particles produced. Electron-positron commonly produce two photons, while proton-antiproton produces many different particles in addition to photons.
    Ref: http://en.wikipedia.org/wiki/Proton_antiproton_annihilation [Broken]
    Ref: http://en.wikipedia.org/wiki/Electron–positron_annihilation
    Last edited by a moderator: May 5, 2017
  19. Jun 25, 2011 #18
    Ok, so annihilation is basically a particle collision, be high or low energy, between a particle and its anti-particle. There is nothing really special about it apart from that, be it the forces involved or the collisions products.

    Last edited by a moderator: May 5, 2017
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