The strings connection: MSSM-like models from strings

From strings to the MSSM

We review recent progress in embedding the supersymmetric standard model into string theory. We discuss how, with the incorporation of certain aspects of grand unification, a search strategy can be developed that allows to efficiently find rather large numbers of promising string vacua. Global string-derived models with the following features are discussed: (i) exact MSSM spectrum below the uni...

Topological Strings from WZW Models

We show that the BRST structure of the topological string is encoded in the “small” N = 4 superconformal algebra, enabling us to obtain, in a non-trivial way, the string theory from hamiltonian reduction of A(1|1). This leads to the important conclusion that not only ordinary string theories, but topological strings as well, can be obtained, or even defined, by hamiltonian reduction from WZW mo...

DF-strings from D3D̄3 as Cosmic Strings

We study Dirac-Born-Infeld type effective field theory of a complex tachyon and U(1)×U(1) gauge fields describing a D3D̄3 system. Classical solutions of straight global and local DFstrings with quantized vorticity are found and are classified into two types by the asymptotic behavior of the tachyon amplitude. For sufficiently large radial distances, one has linearlygrowing tachyon amplitude and ...

Actions for Qcd-like Strings

We introduce a random lattice corresponding to ordinary Feynman diagrams, with 1/p propagators instead of the Gaussians used in the usual strings. The continuum limit defines a new type of string action with two worldsheet metrics, one Minkowskian and one Euclidean. The propagators correspond to curved lightlike paths with respect to the Minkowskian worldsheet metric. Spacetime dimensionality o...

The Delta Operation: From Strings to Trees to Strings