Why is weak nuclear bosons carry the isospin charge?

[AlephClo]

The leptons and hadrons carry the weak isospin charge. What allows the weak bosons do carry the charge? Is it because they have a mass?

 

[king vitamin]

It doesn't have to do with mass - notice that the gluons are massless but they carry color charge. When you consider non-abelian gauge theories (theories where the gauge symmetry is more complicated than that of electromagnetism), your gauge bosons must always carry charge and self-interact.

 

[andrien]

weak isospin charge

Did you mean weak hypercharge or weak isospin?

 

[AlephClo]

King Vitamin,
Thank you for the answer. I am new to particle physics, I am just finishing Deep Down Things from Schaumm. I knew that non-abelian gauge describes the self-interaction; so you are saying that it does not only describes it, but it takes its source, its causation in the non-abelian nature. I will need to dive into gauge theory. Any good introduction book(s), well explained with examples you can recommand? Thanks

Andrien,
I mean the weak isospin.

 

[andrien]

why not start here
http://en.wikipedia.org/wiki/Weak_isospin

 

[AlephClo]

Thank you Andrien

 

[king vitamin]

King Vitamin,
Thank you for the answer. I am new to particle physics, I am just finishing Deep Down Things from Schaumm. I knew that non-abelian gauge describes the self-interaction; so you are saying that it does not only describes it, but it takes its source, its causation in the non-abelian nature. I will need to dive into gauge theory. Any good introduction book(s), well explained with examples you can recommand? Thanks

Well I'd be careful saying that one "causes" the other, they're both aspects of the same theory.

There are two ways to approach non-abelian gauge theory. The most common way (and historically the first) is to begin in analogy to electromagnetism, but insist on your particles transforming in a larger gauge group than in EM. One finds that this theory requires gauge bosons (massless, spin-1), and that their transformations require a self-interaction with a coupling related to the coupling to other particles.

Another way is simply to study the properties of massless spin-1 particles. One finds that the fields describing these particles must have a gauge redundancy to correctly describe the underlying degrees of freedom. So there are many configurations of the field which describe the same physical state. Now if you couple these particles to matter and to themselves, you must do so in a way which reflects this redundancy. In this way you are led uniquely to non-ableian gauge theory (if they do not self-interact, you can only get disjoint copies of electromagnetism). So in this sense, the mere existence of charged massless spin-1 particles implies non-abelian gauge theory, although you need further input to know which gauge group your theory is (experimental data).

This is a very difficult subject so I'm not sure how many laymen resources there are, but Wikipedia tends to have good descriptions. If you have an undergrad background in physics, there are some good introductory particle physics texts.

 

[AlephClo]

Thank you King Vitamin. I have both backgrounds, Math BSc and most of the Physics BSc done in the 80s. Am just retired and getting back physics. I got a copy of Nuclear and Particle Physics by Burchman and Jobes; I will need to work hard to go through it, but I think it is acheiveable (I hope anyways :-). I am open to suggestions.

Thanks again.