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How do having no mass or charge affect structure?

  1. Jul 4, 2012 #1
    I am curious to know if anyone can shed some light on a question I have concerning the neutrino. I am refering only to the electron neutrino and not the others that have theoretical mass values. If it has not mass or charge does that mean it has no dimensions? Or because it has no mass can it have any dimension? Is there any theory on the structure or physical properties of quontum particles? I ask because I am trying to understand some fundamental structural qualities in the quantum world. Thanks in advance for your insight.
  2. jcsd
  3. Jul 4, 2012 #2
    Re: How does having no mass or charge affect structure?

    I should spell check before submiting.....
  4. Jul 4, 2012 #3
    The neutrino, as any other elementary particle (it's not important if they have or not a mass different from zero) is pointlike. This statement is to be read in the following sense: as far as we know right now the neutrino has no internal structure (it's an elementary particle), it means that it isn't composed of any king of "subparticle". In our understanding an elementary particle has no dimension, they are like points, that means just that they dimensions are smaller than any mesure we can realize right now.
  5. Jul 4, 2012 #4


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    Also there is presently no reason to suppose that the mass of the electron neutrino is zero.
  6. Jul 4, 2012 #5
    That makes sense on a basic level. I understand also that the physical dimensions given to the larger particles is based on the motion of quarks. It seems to me that an object with no mass and no charge we might conclude it is more fundamental than a particle with mass and charge? Its kind of like trying to understand the mechanics of a black hole. If an object can be infinitely small why can't it also be infinitely large? Again I am just trying to rap my head around the concept of no charge or mass. Seems to me if it exists and we can measure it or detect it then whe should be interested in its structure. Assuming neutrinos have in fact been detected.
  7. Jul 4, 2012 #6
    Right. I am only refering to the current theory about those values. Is the current value assigned to the electron neutrino such because it is so poorly understood?
  8. Jul 4, 2012 #7
    As I have understood, your difficulties are related to the fact that neutrinos havo no mass and no charge. But this is not a limitation. For example electrons have both mass and charge but they are pointlike too. The importat concept is that there is no such thing as poinlike objects in nature. When we say that an object is pointlike we are talking about a mathematical description, but in nature it is just something whose dimension we are not able to mesure yet because they are very very small.
    It can happen for both massless or massive particle, or for both charged or chargeless particles (consider also that electric charge is not the only charge in nature).
    The concept of mass is a concept completely unrelated to the concept of dimension.
  9. Jul 4, 2012 #8
    Got it... Thanks again for helping. I totally get that mass and dimension are different concepts and in classical mechanics they have a vital relationship. So in quantum mechanics then, I am guessing, The two concepts are not related in such an intrinsic fasion?
  10. Jul 4, 2012 #9
    Neutrinos are understood quite well, actually. We have a theory that says that electron neutrino has non zero mass. Experimental data place upper bound on the mass (according to Wikipedia it's 2.2 eV which is freakishly low).
  11. Jul 4, 2012 #10
    There in is my missunderstanding... I was looking at a chart for sub-atomic particles and it labeled the charge and mass as zero. I looked up your reference and did see the >2.2 eV reference... Thanks
  12. Jul 4, 2012 #11
    Re: How does having no mass or charge affect structure?

    I think you meant "submitting" .... :tongue:
    Last edited: Jul 4, 2012
  13. Jul 4, 2012 #12
    Given that the Higg's boson has been confirmed, shouldn't we be able to predict the theoretical mass of a neutrino?
  14. Jul 4, 2012 #13
    No, the mass is put in by hand. It is the value of the coupling of the neutrino to the Higgs. The Higgs mechanism does not give a prediction for Standard Model masses.
  15. Jul 4, 2012 #14
    Yes... I am sure that given how recent Higgs has been potentially discovered there are several efforts underway to reconsile a lot of unknowns to include the mass of the neutrino.

    Being that my original post had to do with structure are there any theories about the actual structure of sub-atomic particles? I am interested in the basis for charges. I understand that we know particles come in the 3 basic charges but why do they have said charge? It is my opinion that structure would play a key roll in the nature and source of those charges. Or is it a matter of it is what it is and we leave it at that?
    Last edited: Jul 4, 2012
  16. Jul 4, 2012 #15
    Wait.. What? I thought the Higgs was the source of mass in matter?
  17. Jul 4, 2012 #16
    Where is the 'spell check icon'...I have nver found it....as you can tell
  18. Jul 4, 2012 #17
    The following quote from forum user Bill_K should answer your question (from this thread):

  19. Jul 4, 2012 #18
    Ah... ok. That does make sense. But as I read some of the other Higgs posts I understood the Higgs mechanism ie the particle and the field, is fundamental to all sub-atomic particles and it is this mechanism that explains why particles have mass. It was only a theory without proof before its likely discovery here in the last few days. I was under the impression that the Higgs mechanism is what was being used to explain why particles have mass. Correct me if I am wrong.. Which I probably am.. Thanks again for the help in understanding this issue.
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