119502096
N=2 COSET COMPACTIFICATIONS WITH NONDIAGONAL INVARIANTS
We consider four-dimensional string models obtained by tensoring N=2 coset theories with nondiagonal modular invariants. We present results from a systematic analysis including moddings by discrete symmetries.
122296725
Intrinsic normal-ordered vertex operators from the multiloop N-tachyon amplitude
Abstract We construct vertex operators for arbitrary mass level states of the closed bosonic string. Starting from a generalization of the Koba-Nielsen amplitude which is suitable for an arbitrary genus Riemann surface, we read the vertex operators from the residues of the poles for the intermediate states. Since the original expression is metric independent and normal ordered without the need of inventing any regularization scheme, our vertex operators also possess these properties. We discuss their general features.
119116593
Coulomb integrals and conformal blocks in the AdS3-WZNW model
We study spectral flow preserving four-point correlation functions in the AdS3-WZNW model using the Coulomb gas method on the sphere. We present a multiple integral realization of the conformal blocks and explicitly compute amplitudes involving operators with quantized values of the sum of their spins, i.e., requiring an integer number of screening charges of the first kind. The result is given as a sum over the independent configurations of screening contours yielding a monodromy invariant expansion in powers of the worldsheet moduli. We then examine the factorization limit and show that the leading terms in the sum can be identified, in the semiclassical limit, with products of spectral flow conserving three-point functions. These terms can be rewritten as the m-basis version of the integral expression obtained by J. Teschner from a postulate for the operator product expansion of normalizable states in the H3+-WZNW model. Finally, we determine the equivalence between the factorizations of a particular set of four-point functions into products of two three-point functions either preserving or violating spectral flow number conservation. Based on this analysis we argue that the expression for the amplitude as an integral over the spin of the intermediate operators holds beyond the semiclassical regime, thus corroborating that spectral flow conserving correlators in the AdS3-WZNW model are related by analytic continuation to correlation functions in the H3+-WZNW model.
125323277
String propagation in non-compact backgrounds
In this lecture we review some recent developments in non-rational conformal field theory, which allow a description of strings moving in non-compact backgrounds. In particular, we discuss recent progress in the SL(2,R) WZW model, which describes string propagation in AdS3.
1383405
Free field realization of superstring theory on AdS3
Fil: Hofman, Diego M. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina
117028101
Ten Years of AdS/CFT
119193507
Wilson loops in string duals of walking and flavored systems
We consider the vacuum expectation value of Wilson loop operators by studying the behavior of string probes in solutions of type-IIB string theory generated by N{sub c} D5-branes wrapped on an S{sup 2} internal manifold. In particular, we focus on solutions to the background equations that are dual to field theories with a walking gauge coupling as well as for flavored systems. We present in detail our walking solution and emphasize various general aspects of the procedure to study Wilson loops using string duals. We discuss the special features that the strings show when probing the region associated with the walking of the field-theory coupling.
17705233
On the Universality Class of Certain String Theory Hadrons
Abstract Exploiting the gauge/gravity correspondence we find the spectrum of hadronic-like bound states of adjoint particles with a large global charge in several confining theories. In particular, we consider an embedding of four-dimensional N = 1 supersymmetric Yang–Mills into IIA string theory, two classes of three-dimensional gauge theories and the softly broken version of one of them. In all cases we describe the low energy excitations of a heavy hadron with mass proportional to its global charge. These excitations include: the hadron's nonrelativistic motion, its stringy excitations and excitations corresponding to the addition of massive constituents. Our analysis provides ample evidence for the universality of such hadronic states in confining theories admitting supergravity duals. Besides, we find numerically a new smooth solution that can be thought of as a nonsupersymmetric deformation of G 2 holonomy manifolds.
14410217
Flavoring the gravity dual of = 1 Yang-Mills with probes
We study two related problems in the context of a supergravity dual to = 1 SYM. One of the problems is finding kappa symmetric D5-brane probes in this particular background. The other is the use of these probes to add flavors to the gauge theory. We find a rich and mathematically appealing structure of the supersymmetric embeddings of a D5-brane probe in this background. Besides, we compute the mass spectrum of the low energy excitations of = 1 SQCD (mesons) and match our results with some field theory aspects known from the study of supersymmetric gauge theories with a small number of flavors.
33155899
Probing split supersymmetry with cosmic rays
A striking aspect of the recently proposed split supersymmetry is the existence of heavy gluinos which are metastable because of the very heavy squarks which mediate their decay. In this paper we correlate the expected flux of these particles with the accompanying neutrino flux produced in inelastic pp collisions in distant astrophysical sources. We show that an event rate at the Pierre Auger Observatory of approximately 1 yr{sup -1} for gluino masses of about 500 GeV is consistent with existing limits on neutrino fluxes. Such an event rate requires powerful cosmic ray engines able to accelerate particles up to extreme energies, somewhat above 5x10{sup 13} GeV. The extremely low inelasticity of the gluino-containing hadrons in their collisions with the air molecules makes possible a distinct characterization of the showers induced in the atmosphere. Should such anomalous events be observed, we show that their cosmogenic origin, in concert with the requirement that they reach the Earth before decay, leads to a lower bound on their proper lifetime of the order of 100 years, and consequently, to a lower bound on the scale of supersymmetry breaking, {lambda}{sub SUSY}>2.6x10{sup 11} GeV. Obtaining such a bound is not possible in collider experiments.
6639819
D6-branes and M theory geometrical transitions from gauged supergravity
We study the supergravity duals of supersymmetric theories arising in the world-volume of D6-branes wrapping holomorphic two-cycles and special lagrangian three-cycles within the framework of eight-dimensional gauged supergravity. When uplifted to 11d, our solutions represent M-theory on the background of, respectively, the small resolution of the conifold and a manifold with G2 holonomy. We further discuss on the flop and other possible geometrical transitions and its implications.