Are the W bosons charged before symmetry breaking?

[franoisbelfor]

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!

Francois

 

[Vanadium 50]

"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.

 

[franoisbelfor]

"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.

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.

François

 

[arivero]

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..

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.