Talk:Chiral perturbation theory
Reviewer A report
This article is written by one of the world experts in chiral perturbation theory. Consequently, the contents of the article reflects competence and the style is professional. The academic level of presentation is more understandable to a general readership than previous review articles by the same author. Nevertheless, most sections of this article will only be fully comprehensible to theoretical physicists with a background in quantum field theory. But, I guess, there is no way to avoid this dilemma unless one boils the presentation down to the level of a popular science article which, I understand, is not the purpose of Scholarpedia. A person with a general physics background will, however, get some idea of what chiral perturbation theory is about from the first few pages of the article.
In conclusion, I recommend the publication of this article.
I found the following minor technical issues and typos that should be taken care of prior to publication:
In the first paragraph of the article, the abbreviations NJL and AdS/CFT are used. I recommend to explain these abbreviations when used first.
Since the article does not have page numbers, I will in the following identify locations by equation numbers.
One paragraph below Eq. (9): …, and the state |0 out,f>, where …
Above Eq. (23): … involving 0, 2, 4, \ldots pion fields:
Below Eq. (35): “… Lagrangian in equation (19) – the relevant vertices are those in the second line.“ Which second line?
Further reading; This list does not contain much about recent progress in nuclear forces derived from Chiral perturbation theory. Therefore, I suggest to add the following (very pedagogical) article to this list:
Machleidt, R and Entem, D R (2011), Chiral effective field theory and nuclear forces, Physics Reports 503: 1. arXiv:1105.2919.
Reviewer B report
Hello, you can publish the review as is. I have three small optional comments given below.
1) In the paragraph following (9). The vacuum |0> is the full QCD vacuum, not the vacuum of QCD perturbation theory.
2) The comment that the up down mass difference does not appear at lowest order is only true for pion physics, maybe this can be mentioned explicitly here (even though of course the whole discussion is only for pion physics at this point)
3) There is no reference to the original papers for the Gell-Mann--Okubo formula.
Thank you for the referee reports. The comments made by the referees are very useful and I have modified the text accordingly. All but one of the changes are self-evident. The exception is comment #1 of referee B
"1) In the paragraph following (9). The vacuum |0> is the full QCD vacuum, not the vacuum of QCD perturbation theory."
The passage "... the system was in the unperturbed ground state in the remote past" gave the reader the impression that the vacuum occurring here is a Fock space vector of perturbation theory. To avoid this, I have replace this passage by "... the system was in the state of lowest energy in the remote past". I think that this accounts for the comment.