Calculation of Callan-Symanzik Beta function of QED/QCD to one loop order

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Discussion Overview

The discussion revolves around the calculation of the Callan-Symanzik beta function for Quantum Electrodynamics (QED) and Quantum Chromodynamics (QCD) at one-loop order, particularly focusing on the literature and methodologies used in this context. Participants express concerns about the rigor and assumptions in existing literature, especially in Peskin's work.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant questions the rigor and assumptions in Peskin's treatment of the Callan-Symanzik beta function, suggesting it contains mistakes.
  • Another participant argues that standard textbooks, including Peskin, require readers to fill in details through calculations, implying that the learning process involves some ambiguity.
  • There is a mention of the Dyson proposed perturbative expansion as a starting point in Peskin's approach.
  • A participant emphasizes the importance of constructive feedback rather than criticism, expressing frustration over perceived attacks on their understanding.
  • Concerns are raised about the presence of errors in textbooks, including Peskin, with a reference to errata available on the author's site.
  • One participant offers to help decipher parts of Peskin's work that are problematic for others and to assist with technical details of the calculations.

Areas of Agreement / Disagreement

Participants express differing views on the adequacy of Peskin's treatment of the subject, with some defending its standard status while others critique its rigor and clarity. The discussion remains unresolved regarding the best resources for understanding the Callan-Symanzik beta function.

Contextual Notes

Participants acknowledge that textbooks often contain mistakes and that the understanding of complex topics like the Callan-Symanzik beta function may depend on individual interpretation and experience with the material.

evgkr
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Hi everybody.
I was given a project to calculate Callan-Symanzik beta function of QED and QCD (with massless fermions) to one loop order. This problem is actually solved in Peskin, BUT without the needed rigor, plus with funny assumptions and also a few mistakes.
I have tried for a long time to find where this topic is covered in the manner it is covered in Peskin, but it seems that Peskin's access to the problem although not quite clear to me is pretty original. (Even Callan's original article is not sharing the same access)
My question is: Does anyone knows where I can find literature dealing with Renormalization group from Callan-Symanzik's point og view, and most simillar to Peskin's access to that issue ?

Thanks ahead.
 
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Originally posted by evgkr
...project to calculate Callan-Symanzik beta function of QED and QCD (with massless fermions) to one loop order...seems that Peskin's access to the problem although not quite clear to me is pretty original...

I don't have peskin, but they all do it pretty much the same standard way, so there's no need to handcuff yourself to peskin.

Originally posted by evgkr
...problem is actually solved in Peskin, BUT without the needed rigor...

Well, any good textbook is going to require you fill in some of the details since it's by doing calculations that you learn.

Originally posted by evgkr
...plus with funny assumptions and also a few mistakes.

Since peskin has been the standard graduate textbook on the subject for quite a while now. this probably indicates that you don't understand something. I'd start by resolving these issues.
 
doesnt Peskin start with the usual Dyson proposed perturbative expansion?
 
jeff
I I am quite new in this forum, but I supose that the purpose of this forum is to supply answers to questions and not ctiticizm on ignorance. My question was: Does anybody knows literature with simillar to Peskin's access to C-S equation and NOT whenever I understand or not what is written there or how much calculations I must do to learn. And about your comment on mistakes, I do not know if you are familiar with the fact that EVERY books have mistakes, and also Peskin is full of them, look at the errata in Peskin's site, if you do not believe me.
In the future,please, leave these comments to yourself if you have nothing usefull to prupose.

All
I have managed to close the gaps in this area.
Thanks for help.
 
Last edited:
Originally posted by evgkr
jeff
I I am quite new in this forum, but I supose that the purpose of this forum is to supply answers to questions and not ctiticizm on ignorance.

What I posted was based on my own personal experience learning and teaching and was meant to help, not to offend or criticize and I appologize for making you feel attacked. I just didn't want you spending too much time looking for the "ideal" treatment of this subject with all the details spelled out etc because the only place you'll find that is in the notes of some other student who's made the same calculation.

Originally posted by evgkr
And about your comment on mistakes, I do not know if you are familiar with the fact that EVERY books have mistakes, and also Peskin is full of them, look at the errata in Peskin's site, if you do not believe me.

There may be typos remaining in the book, but I'm pretty sure the errata and the book contain no serious logical errors. Can you say something about the parts of peskin that are bothering you? Maybe I can help decipher them. I can also help you with the technical details of these calculations if you want.

Originally posted by evgkr
In the future,please, leave these comments to yourself if you have nothing usefull to prupose.

Just keep in mind that you don't know me and therefore couldn't possibly know for certain how my post was intended. From this standpoint your reaction was presumptious and unjustified and unlike my comments, clearly meant to attack. Likewise, I don't know you, and in the future I'll be more careful with you, but if you habitually fly off the handle like this I definitely won't be wasting any of my time helping you.
 

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