D-brane solitons in supersymmetric sigma models

Massive D=4, N=2 supersymmetric sigma models typically admit domain wall (Q-kink) solutions and string (Q-lump) solutions, both preserving 1/2 supersymmetry. We exhibit a new static 1/4 supersymmetric "kink-lump" solution in which a string ends on a wall, and show that it has an effective realization as a bion of the D=4 super DBI action. It is also shown to have a time-dependent Q-kink-lump generalization which reduces to the Q lump in a limit corresponding to infinite BI magnetic field. All these 1/4 supersymmetric sigma-model solitons are shown to be realized in M theory as calibrated, or "Q calibrated," M5-branes in an M-monopole background.