Relation between symmetry, charges and one-particle states

[alphaone]

Hi,
I recently saw an author make the following statement:
If the symmetry leaves the 1-particle states invariant then its associated charge Q acts on the 1-particle states |p> such that Q|p> = 0
This statement is nontrivial to me, so if anybody could show me how it works please let me know.

 

[alphaone]

Figured this out myself already, so no reply needed.