What does h.c. mean in Lagrangians?

[hamiltonjr]

Meaning of "h.c." in Lagrangians (& elsewhere?)

I am fairly new to particle physics and am puzzled by an abbreviation I often see in Lagrangians here (though it may not be particular to that application): " + h.c." is tacked on after other terms. What does this denote? Apologies if I've missed something very simple, and thanks for the help either way!

 

[ZapperZ]

This is not unique to particle physics. All it means is that there are additional terms which are the hermitian conjugate of the terms that have already been written.

Zz.

 

[chrispb]

What Zz said. The Hamiltonian should be a hermitian operator, but note that if we have any (well-behaved) operator A, then A + Adagger is hermitian. So the notation is both a convenient way of making sure we have a hermitian operator and a convenient shorthand to omit half the terms present.