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Where are the anti-particles in a nuclie?

  1. Jan 4, 2009 #1
    Hello. Where are the anti-particles in a nuclie?Are they virtual particles or are there pair production for every particle-antiparticle? Where do the positron lie in an electron? How does different forms of raditaon account for production of these anti-paricles? For example, how does beta plus decay occur?? I mean how can a positron be emmited?? And how does pair production occur; where does the anti-particle come from or how does it get created?
     
    Last edited: Jan 4, 2009
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  3. Jan 4, 2009 #2

    DrChinese

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    Re: Anti-Particles

    A lot of questions, maybe this will help a bit.

    1. Normal matter (like what we see around us) does not contain anti-particles (which is called anti-matter).

    2. Virtual particles normally appear in pairs - a particle and a matching anti-particle - which normally annihilate and leave nothing behind in the way of matter or energy. I.e. no net new matter or anti-matter is created this way.

    3. High energy particle colliders (atom smashers) can create anti-matter (as well as matter) which can actually be harnessed for a period of time in the right circumstances.

    4. Some nuclear reactions, as well as beta decay of a neutron, generate anti-matter (such as an anti-neutrino - which is a ghostly particle which does not much interact with matter).
     
  4. Jan 4, 2009 #3
    Re: Anti-Particles

    Thank you for clearing up any doubt, but as you say in particle accelators generating antiparticles, how does taht happen and why does that happen. Obviously, some'thing' is generating teh creation of antiparticles. Is it due to the magnitude of the collision which undergo electromagnetic interactions that create antiparticles? If so, how?
     
  5. Jan 4, 2009 #4
    Re: Anti-Particles

    I thought in Qm (basics) that phtons are generated due to law of conservation of energy and spin... well then wouldn't photons be virtual particles holding a certain degree of magnitude. If so, how can a photon have an antiparticle as it is chargless and massless, and is that antiparticle created just another phton. And doesn't annhilations give off high energy photons..
     
  6. Jan 4, 2009 #5
    Re: Anti-Particles

    Also, Where do these antiparticles come from when creted from radioactive decay, and more specifically, beta plus decay?
     
  7. Jan 4, 2009 #6

    DrChinese

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    Re: Anti-Particles

    1. When ordinary matter collides at very high velocity (near the speed of light), all kinds of particles can emerge from the collision. Some emerging particles can be anti-matter too. There are conservation laws in effect. So mass/energy, charge, and certain other things are conserved in total. But the result does not just depend on electromagnetism, it also depends on the weak nuclear force and sometimes the strong force.

    2. Photons are their own anti-particles. Yes, seems a bit weird. But ordinary photons are not considered virtual particles, they are "real".
     
  8. Jan 4, 2009 #7
    Re: Anti-Particles

    Oh.. ok so due to the conservation of mass, etc, antimatter is formed to hold these principles. ok.. thank you on my ambiguity! Now i also have a lot more questions on quantum mechanics. ANd note, plese when you answer, assume only basic knowledge on EM and Qm , but full on Gravity...

    Because photons are massless, does taht create particle-wave duality?
    Plese explain Local U(1) - guage invariance as in another thread i made, i asked this question, though i *coughsadlycough* did not understand one bit..
     
  9. Jan 4, 2009 #8

    Vanadium 50

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    Re: Anti-Particles

    It really would be better to keep that discussion on that thread, rather than getting them all intertwined together.
     
  10. Jan 4, 2009 #9
    Re: Anti-Particles

    Sorry..but then again science itself is always conencted to all other internal branches
     
  11. Jan 4, 2009 #10

    Vanadium 50

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    Re: Anti-Particles

    I don't think that's a very good rationale for hijacking another thread. You wouldn't post a message about chemistry in a section titled "botany", would you?

    Also, I will not respond to private messages to clarify something that's said on a public thread. (Other may feel the same way) If you have questions, chances are other people do too, and trying to address them one person at a time is horribly inefficient.
     
  12. Jan 5, 2009 #11

    malawi_glenn

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    Re: Anti-Particles

    The reason for why you don't understand how photons are their own antiparticles is that you perhaps don't even know what antiparticles ARE.

    Antiparticles are required to preserved causality in quantum field theory, see Peskin page 27-29
     
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