BPS Domain Walls in Models with Flat Directions

We consider BPS domain walls in the four dimensional N=1 supersymmetric models with continuous global symmetry. Since the BPS equation is covariant under the global transformation, the solutions of the BPS walls also have the global symmetry. The moduli space of the supersymmetric vacua in such models have non-compact flat directions, and the complex BPS walls interpolating between two disjoint flat directions can exist. We examine this possibility in two models with global O(2) symmetry, and construct the solution of such BPS walls.Comment: LaTeX file, 19 pages, 8 eps figures, published versio

An Exact Solution of BPS Domain Wall Junction

An exact solution of domain wall junction is obtained in a four-dimensional N=1 supersymmetric U(1) X U(1)' gauge theory with three pairs of chiral superfields which is motivated by the N=2 SU(2) gauge theory with one flavor perturbed by an adjoint scalar mass. The solution allows us to evaluate various quantities including a new central charge Y_k associated with the junction besides Z_k which appears already in domain walls. We find that the new central charge Y_k gives a negative contribution to the mass of the domain wall junction whereas the central charge Z_k gives a dominant positive contribution. One has to be cautious to identify the central charge Y_k alone as the mass of the junction.Comment: LaTeX file, 13 page, 1 ps figur

Wall Solution with Weak Gravity Limit in Five Dimensional Supergravity

In five-dimensional supergravity, an exact solution of BPS wall is found for a gravitational deformation of the massive Eguchi-Hanson nonlinear sigma model. The warp factor decreases for both infinities of the extra dimension. Thin wall limit gives the Randall-Sundrum model without fine-tuning of input parameters. We also obtain wall solutions with warp factors which are flat or increasing in one side, by varying a deformation parameter of the potential.Comment: Typo corrected, reference added, 13pages, 5 figure

An Exact Solution of BPS Junctions and Its Properties

We have obtained an exact solution for the BPS domain wall junction for a N=1 supersymmetric theory in four dimensions and studied its properties. The model is a simplified version of the N=2 SU(2) gauge theory with N_f=1 broken to N=1 by the mass of the adjoint chiral superfield. We define mode equations and demonstrate explicitly that fermion and boson with the same mass have to come in pairs except massless modes. We work out explicitly massless Nambu-Goldstone (NG) modes on the BPS domain wall junction. We find that their wave functions extend along the wall to infinity (not localized) and are not normalizable. It is argued that this feature is a generic phenomenon of NG modes on domain wall junctions in the bulk flat space in any dimensions. NG fermions exhibit a chiral structure in accordance with unitary representations of (1, 0) supersymmetry algebra where fermion and boson with the same mass come in pairs except massless modes which can appear singly.Comment: LaTeX file, 10 page, 3 eps figure; uses espcrc2.sty (twocolumn). Talk presented by N. Sakai at the SUSY 30 workshop in Minnesota, October 16-27, 2000. To appear in Nuclear Physics B (Proceedings Supplement). References adde