Branched covers bounding rational homology balls

Prime power fold cyclic branched covers along smoothly slice knots all bound rational homology balls. This phenomenon, however, does not characterize slice knots. In this paper, we give a new construction of non-slice knots that have the above property. The sliceness obstruction comes from computing twisted Alexander polynomials, and we introduce new techniques to simplify their calculation.
Comment: 19 pages, 5 figures, Version 2: Minor changes to abstract and introduction. Added references on knots that are not concordant to their reverses