Strings, branes, extra dimensions and discrete symmetries
- Alon Faraggi (University of Liverpool)
The recent so called dS swampland conjecture states that string theory does not give rise to dS vacua. Therefore the dark energy in our universe should arise from a quintessence field. After reviewing the conjecture I will discuss its short-comings and the current status of dS vacua in string theory.
We investigate under which conditions the one-loop cosmological constant vanishes for heterotic strings on non-supersymmetric toroidal orbifolds. To obtain model-independent results, we require that each orbifold sector preserves at least a single Killing spinor, but not always the same one. The existence of such Killing spinors is related to the representation theory of the point groups that...
A natural way to embed flavor symmetry and CP violation in string theory is presented. In the low energy effective theory CP is broken by the presence of heavy string modes and CP violation is the result of an interplay of CP and flavor symmetry. As an application, CP violating decays of heavy string modes are briefly discussed that could give rise to a cosmological matter-antimatter asymmetry.
We present the conditions for moduli stability in perturbative open string theory with initially 16 superchages, when supersymmetry is spontaneously broken.
Over the past few years an analysis of heterotic string vacua for different types of SO(10) subgroup models has been performed within the free fermionic string formalism. Using a process of random generation of GSO matrices, samples of models from flipped SU(5), Pati-Salam, Standard-like and, most recently, left-right symmetric models have all been classified. In this talk I will briefly...