  Balance functions have been measured for charged particle pairs, identified
charged pion pairs, and identified charged kaon pairs in Au+Au, d+Au, and p+p
collisions at $\sqrt{s_{NN}}$ = 200 GeV at the Relativistic Heavy Ion Collider
using the STAR detector. These balance functions are presented in terms of
relative pseudorapidity, $\Delta \eta$, relative rapidity, $\Delta y$, relative
azimuthal angle, $\Delta \phi$, and invariant relative momentum, $q_{\rm inv}$.
In addition, balance functions are shown in terms of the three components of
$q_{\rm inv}$: $q_{\rm long}$, $q_{\rm out}$, and $q_{\rm side}$. For charged
particle pairs, the width of the balance function in terms of $\Delta \eta$
scales smoothly with the number of participating nucleons, while HIJING and
UrQMD model calculations show no dependence on centrality or system size. For
charged particle and charged pion pairs, the balance functions widths in terms
of $\Delta \eta$ and $\Delta y$ are narrower in central Au+Au collisions than
in peripheral collisions. The width for central collisions is consistent with
thermal blast-wave models where the balancing charges are highly correlated in
coordinate space at breakup. This strong correlation might be explained either
by delayed hadronization or by limited diffusion during the reaction.
Furthermore, the narrowing trend is consistent with the lower kinetic
temperatures inherent to more central collisions. In contrast, the width of the
balance function for charged kaon pairs in terms of $\Delta y$ shows little
centrality dependence, which may signal a different production mechanism for
kaons. The widths of the balance functions for charged pions and kaons in terms
of $q_{\rm inv}$ narrow in central collisions compared to peripheral
collisions, which may be driven by the change in the kinetic temperature.
