Supergravity and a confining gauge theory: duality cascades and χSB-resolution of naked singularities

We revisit the singular IIB supergravity solution describing M fractional3-branes on the conifold [hep-th/0002159]. Its 5-form flux decreases, which weexplain by showing that the relevant \NN=1 SUSY SU(N+M)xSU(N) gauge theoryundergoes repeated Seiberg-duality transformations in which N -> N-M. Far inthe IR the gauge theory confines; its chiral symmetry breaking removes thesingularity of hep-th/0002159 by deforming the conifold. We propose anon-singular pure-supergravity background dual to the field theory on allscales, with small curvature everywhere if the `t Hooft coupling g_s M islarge. In the UV it approaches that of hep-th/0002159, incorporating thelogarithmic flow of couplings. In the IR the deformation of the conifold givesa geometrical realization of chiral symmetry breaking and confinement. Wesuggest that pure \NN=1 Yang-Mills may be dual to strings propagating at smallg_s M on a warped deformed conifold. We note also that the standard modelitself may lie at the base of a duality cascade.Comment: 38 pages; v2: Discussion of screening effects for N/M noninteger added to Secs. 4, 5. v3: Minor corrections to v2 changes (Sec. 5.2) v4 Additional comments about (2,1) forms, references adde