  We discuss the moduli-dependent couplings of the higher derivative F-terms
$(\Tr W^2)^{h-1}$, where $W$ is the gauge N=1 chiral superfield. They are
determined by the genus zero topological partition function $F^{(0,h)}$, on a
world-sheet with $h$ boundaries. By string duality, these terms are also
related to heterotic topological amplitudes studied in the past, with the
topological twist applied only in the left-moving supersymmetric sector of the
internal $N=(2,0)$ superconformal field theory. The holomorphic anomaly of
these couplings relates them to terms of the form $\Pi^n({\rm Tr}W^2)^{h-2}$,
where $\Pi$'s represent chiral projections of non-holomorphic functions of
chiral superfields. An important property of these couplings is that they
violate R-symmetry for $h\ge 3$. As a result, once supersymmetry is broken by
D-term expectation values, $(\Tr W^2)^2$ generates gaugino masses that can be
hierarchically smaller than the scalar masses, behaving as $m_{1/2}\sim m_0^4$
in string units. Similarly, $\Pi{\rm Tr}W^2$ generates Dirac masses for
non-chiral brane fermions, of the same order of magnitude. This mechanism can
be used for instance to obtain fermion masses at the TeV scale for scalar
masses as high as $m_0\sim{\cal O}(10^{13})$ GeV. We present explicit examples
in toroidal string compactifications with intersecting D-branes.
