31 research outputs found
D-Instantons and asymptotic geometries
The large N limit of D3-branes is expected to correspond to a superconformal
field theory living on the boundary of the anti-de Sitter space appearing in
the near-horizon geometry. Dualizing the D3-brane to a D-instanton, we show
that this limit is equivalent to a type IIB S-duality. In both cases one
effectively reaches the near-horizon geometry. This provides an alternative
approach to an earlier derivation of the same result that makes use of the
properties of a gravitational wave instead of the D-instanton.Comment: 17 pages, LaTeX, 1 figure, minor corrections and refs adde
The scalar and pseudoscalar sector in a five-dimensional approach to chiral symmetry breaking
Premi a l'excel·lĂšncia investigadora. Ămbit de les CiĂšncies Experimentals. 2008We study the scalar and pseudoscalar sector in a five-dimenional model describing chiral symmetry breaking. We calculate the scalar and pseudoscalar two-point correlator, the mass spectrum and interactions. We also obtain the scalar and pseudoscalar contributions to the coefficients of the chiral lagrangian and determine the scalar form factor of the pseudo-Goldstone bosons. Most quantities show a good agreement with QC