There are quite subtle gauge anomaly cancellations in the standard model. Does anybody know a good summary about the algebraic constraints for number of fermions per generation, value of electroweak charges, etc.?
Weinberg, QFT Vol II, all of Chapter 22. (To the extent that anything written by Weinberg may be called a "summary". ) In particular, pp.385-386 lists constraints for the Standard Model.
google was my friend, too: http://isites.harvard.edu/fs/docs/icb.topic1146666.files/IV-6-Anomalies.pdf - chap. 5 http://www.maths.dur.ac.uk/~dma0saa/lecture_notes.pdf - chap. 8.2 http://arxiv.org/pdf/0802.0634.pdf - chap. 7.3