Recent content by jacopo23

Could you please explain this point? After the answer given by Ben Niehoff I had understood that even if the gauge bosons got a mass, the global symmetry would be saved and so there would still be a noether current. I haven't done the calculation but I expect that in general this current is...

Ah ok, now I see. You are right, thank you :)!

Yes, under a global transformation \partial_{\mu} U = 0 but since the gauge transformation is A_{\mu} \rightarrow U A_{\mu} U^{+}-i (\partial_{\mu} U ) U^{+} , then under a global transformation the first term gives m^2 A_{\mu} A^{\mu} \rightarrow m^2 U A_{\mu} A^{\mu} U^{+} that is...

You could have a look on a topic called stochastic quantization, you can also read the preface of a book by Mikio Namiki about these things. Ciao.

Hi thank you for the answer but could you be more clear please :) ? I'm not so very into the subjet. I study other things, but had to study a little of field theory for an exam. Do you maybe mean that the mass term emerging from spontaneous symmetry breaking does not enter in the lagrangian...

I was just wondering that if the theory was not abelian, for example SU(2), when the gauge bosons get masses the lagrangian is not invariant under the global symmetry anymore. In fact, under a gauge transformation, A_{\mu} \rightarrow U A_{\mu} U^{+} - i (\partial_{\mu} U) U^{+} and if the...

Hi, thank you for the answer. I think you are right. Ciao.

What if in the elettroweak theory we broke U(1) too? I read sometimes that electric charge would not be conserved anymore. Anyway, if the photon got a mass, even if U(1) gauge symmetry is broken, QED lagrangian would still be invariant under global U(1) transformation, and we should still have...