Chiral Symmetry Breaking in Brane Models

We discuss the chiral symmetry breaking in general intersecting Dq/Dp brane models consisting of N_c Dq-branes and a single Dp-brane with an s-dimensional intersection. There exists a QCD-like theory localized at the intersection and the Dq/Dp model gives a holographic description of it. The rotational symmetry of directions transverse to both of the Dq and Dp-branes can be identified with a chiral symmetry, which is non-Abelian for certain cases. The asymptotic distance between the Dq-branes and the Dp-brane corresponds to a quark mass. By studying the probe Dp-brane dynamics in a Dq-brane background in the near horizon and large N_c limit we find that the chiral symmetry is spontaneously broken and there appear (pseudo-)Nambu-Goldstone bosons. We also discuss the models at finite temperature.Comment: 29pages, 14figures. v2: a reference added. v3: 27pages, 12figures, two references added, discussions on s=q configurations are corrected. v4: minor change in Sec.

Super Weyl Anomalies in the AdS/CFT Correspondence

Anomalies of N = (4,4) superconformal field theories coupled to a conformal supergravity background in two dimensions are computed by using the AdS/CFT correspondence. We find that Weyl, axial gauge and super Weyl transformations are anomalous, while general coordinate, local Lorentz, vector gauge and local super transformations are not. The coefficients of the anomalies show that the superconformal field theories have the central charge expected in the AdS/CFT correspondence.Comment: 16 pages, LaTeX, references added and typos correcte

Supersymmetry in the AdS/CFT Correspondence

We study how local symmetry transformations of (p, q) anti de Sitter supergravities in three dimensions act on fields on the two-dimensional boundary. The boundary transformation laws are shown to be the same as those of two-dimensional (p, q) conformal supergravities for p, q \leq 2. Weyl and super Weyl transformations are generated from three-dimensional general coordinate and super transformations.Comment: 11 pages, LaTe

Higher derivative couplings of hypermultiplets

We construct the four-derivative supersymmetric extension of $(1,0), 6D$ supergravity coupled to Yang-Mills and hypermultiplets. The hypermultiplet scalars are taken to parametrize the quaternionic projective space $Hp(n)=Sp(n,1)/Sp(n)\times Sp(1)_R$. The hyperscalar kinetic term is not deformed, and the quaternionic K\"ahler structure and symmetries of $Hp(n)$ are preserved. The result is a three parameter Lagrangian supersymmetric up to first order in these parameters. Considering the case of $Hp(1)$ we compare our result with that obtained from the compactification of $10D$ heterotic supergravity on four-torus, consistently truncated to $N=(1,0)$, in which the hyperscalars parametrize $SO(4,1)/SO(4)$. We find that depending on how $Sp(1) \subset Sp(1,1)$ is embedded in $SO(4)$, the results agree for a specific value of the parameter that governs the higher derivative hypermultiplet couplings.Comment: 29 page

Superconformal Sigma Models in Higher Than Two Dimensions

Rigidly superconformal sigma models in higher than two dimensions are constructed. These models rely on the existence of conformal Killing spinors on the $p+1$ dimensional worldvolume $(p\le 5)$, and homothetic conformal Killing vectors in the $d$--dimensional target space. In the bosonic case, substituting into the action a particular form of the target space metric admitting such Killing vectors, we obtain an action with manifest worldvolume conformal symmetry, which describes the coupling of $d-1$ scalars to a conformally flat metric on the worldvolume. We also construct gauged sigma models with worldvolume conformal supersymmetry. The models considered here are generalizations of the singleton actions on $S^p\times S^1$, constructed sometime ago by Nicolai and these authors.Comment: 16 pages, plain te