Concept of a renormalizable theory in Weinberg's feild theory book

[nughret]

I have just started to study the concept of a renormalizable theory in Weinberg's field theory book. I am not sure if my understanding of the process is correct and would like some additional explanation or corrections; As far as I understand in any theory there will be unrenormalizable interactions, however these infinities will be removed if we add all possible interactions allowed by gauge and lorentz symmetry to the lagrangian. I firstly don't understand how this process exactly works.
Secondly it appears to me that it is then claimed that even in an unrenormalizable theory such a lagrangian will lead to finite interaction terms and this part i really don't get, but i am not sure if i have just misunderstood this.
Any help would be greatly appreciated.

 

[Avodyne]

As far as I understand in any theory there will be unrenormalizable interactions

No, in a renormalizable theory, there are no nonrenormalizable interactions.

Weinberg is not the best place to start. I suggest Srednicki.

 

[Haelfix]

Weinberg is probably referring to dimension >4 terms that generically do appear (they are consistent with gauge and lorentz invariance). These of course are nonrenormalizable, though heavily suppressed by some large mass scale and so can be safely integrated out in an effective theory.

 

[Demystifier]

Weinberg is not the best place to start. I suggest Srednicki.

I agree. Personally, I suggest A. Zee, "QFT in a nutshell".

 

[nughret]

Thanks I will have a look into these books, i was wondering though if anyone had a source that was aimed at renormalization specifically rather than the entire basics of field theory

 

[Demystifier]

Thanks I will have a look into these books, i was wondering though if anyone had a source that was aimed at renormalization specifically rather than the entire basics of field theory

There is such a textbook: Collins "Renormalization".
But it makes sense to read it only if you are already familiar with other basics of QFT.