Friday, 16 October 2015

group theory - What exactly means "is a singlet under $SU(N)$"



I don't get a grip of what that exactly means. What IS an abstract singlet, doublet,... under $SU(N)$ or other groups?



Answer



"Singlet under $SU(N)$" means that the related representation is invariant under $SU(N)$.


"Doublet" is related in general to $SU(2)$, and corresponds to the fundamental ($2$- dimensional) representation of $SU(2)$



For instance, looking at the "weak interaction", left-handed particles transform as a doublet under $SU(2)_L$ , while right-handed particles transform as a singlet under $SU(2)_L$


No comments:

Post a Comment

Understanding Stagnation point in pitot fluid

What is stagnation point in fluid mechanics. At the open end of the pitot tube the velocity of the fluid becomes zero.But that should result...