  We study sum rules for charge exchange operators of the Gamow-Teller and
Fermi type and explore what can be learned from them about proton-neutron
pairing in T=0 and T=1 channels. We consider both energy weighted (EWSR) and
non-energy weighted (NEWSR) sum rules. We use a schematic Hamiltonian to stress
the distinctive roles of T=1 and T=0 pair interactions and correlations in the
sum rules. Numerical results for 44Ti are presented for both schematic and
realistic interactions.
