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Do elementary particles have attributes?

  1. Mar 4, 2006 #1


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    Supposing there are some most elementary particles which are not composed of subparticles, would these have any attributes?
    I mean "attributes of a particle" as something whose value i can determine by looking exclusively at that particle. For example, under this definition, "position" isn't really an attribute of a particle because i can't, by looking exclusively at a particle, determine it's position. I'm forced to compare and relate my particle to other particles in the universe (such as the my own constituent particles) to attempt to determine a value for "position".
    The case seems to be the same for momentum, mass and spin. These last three actually seem to require interaction with other particles in order for us to determine their value.
    I guess the question is, if there were only a single elementary particle in the universe, what attributes would it have? Do particles really have any attributes encoded in them, or are attributes only something that we invent by relating particles to eachother?
    Seems to me like elementary particles don't have any actual "attributes". If so then what's the difference between matter and space? What is it that makes a particle a particle?
  2. jcsd
  3. Mar 4, 2006 #2


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    In the Standard model of Particles and interactions, elementary particles have certain attributes which correspond to quantum numbers, meaning that eigenvalues of various operators describing observables are used to identify a particle: example mass corresponds to the square of the momentum operator, electric charge to the electric charge operator, spin and helicity are linked to Pauli-Liubarsky operator,etc...

  4. Mar 4, 2006 #3


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    Essentially, all possible properties of physical objects can only be defined through interactions with other particles/systems.

    Moreover, it is only possible to define such properties if there are differences in the way two (or more) particles interact.
  5. Mar 4, 2006 #4

    Tom Mattson

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    For the currently accepted values of the 'attributes' of fundamental particles, see the particle listings provided by the Particle Data Group.
  6. Mar 8, 2006 #5
    Particle properties?

    This doesn't answer Job's question:
    Those particle listings tell us how particles "look" and "behave" in relation to measurement devices and thus (ultimately) in relation to other particles. If we think of a particle in splendid isolation, out of relation to everything else (including our eyes and central nervous systems considered as measurement devices), it has no properties whatsoever, for all particle properties are ultimately relational. ahrkron got it right:
    For more information take a look http://www.flyservers.com/members5/thisquantumworld.com/index.htm.
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