  We construct a new family of knot concordance invariants $\theta^{(q)}(K)$,
where $q$ is a prime number. Our invariants are obtained from the equivariant
Seiberg-Witten-Floer cohomology, constructed by the author and Hekmati, applied
to the degree $q$ cyclic cover of $S^3$ branched over $K$. In the case $q=2$,
our invariant $\theta^{(2)}(K)$ shares many similarities with the knot Floer
homology invariant $\nu^+(K)$ defined by Hom and Wu. Our invariants
$\theta^{(q)}(K)$ give lower bounds on the genus of any smooth, properly
embedded, homologically trivial surface bounding $K$ in a definite $4$-manifold
with boundary $S^3$.
