  In 2015, the PHENIX collaboration has measured single-spin asymmetries for
charged pions in transversely polarized proton-proton collisions at the center
of mass energy of $\sqrt{s}=200$ GeV. The pions were detected at central
rapidities of $|\eta|<0.35$. The single-spin asymmetries are consistent with
zero for each charge individually, as well as consistent with the previously
published neutral-pion asymmetries in the same rapidity range. However, they
show a slight indication of charge-dependent differences which may suggest a
flavor dependence in the underlying mechanisms that create these asymmetries.
