Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Are the W bosons charged before symmetry breaking?

  1. Aug 16, 2008 #1
    When the SU(2) symmetry is broken
    by the Higgs mechanism,
    the W bosons acquire mass
    and become the well-known W^+ and W^-
    bosons discovered at CERN.

    So before the breaking, the Ws had no mass.
    Did they have charge?

    If yes: No particle is known
    without mass but with charge. Are the W
    before symmetry breaking the first?

    If no: How does charge arise through
    symmetry breaking?

    Thanks for any help!

  2. jcsd
  3. Aug 16, 2008 #2

    Vanadium 50

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor
    2017 Award

    "Before" is maybe not the best word. There was, as far as we know, no time in the universe when the SU(2) X U(1) symmetry was unbroken. The time you are referring two is the time it takes to do the derivation - so your question really is closer to "between steps 5 and 6 in the derivation, do the w's have charge?" Note that these are not physical states.

    One can do a similar thing with fermions and treat the left-handed and right-handed chiral projections as separate particles. These are also charged and massless - and also not physical states.
  4. Aug 16, 2008 #3
    Thank you! I see my mistake. So at energies far above the symmetry breaking scale, the W is still massive and charged, am I correct? The books sometime give the impression that at high energy, the symmetry is unbroken... I really got something mixed up there.

  5. Aug 16, 2008 #4


    User Avatar
    Gold Member

    Horrible books. It is as trying to learn of God by reading the Bible.

    Anyway, yes, the point is that at very high energy the W is still massive but its mass is small for the calculations being done, so it can be taken as zero in order to simplify the calculation. But note that you can not put its charge to zero.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook