# String Theory/M-Theory

The Standard Model has done an excellent job of explaining all elementary particle interactions discovered so far, but it is widely believed that there is much physics yet to be discovered beyond the Standard Model. In particular, there are hints that a new symmetry called "supersymmetry" may play an important role in fundamental physics. Also, there is evidence that all of the forces are unified into a single force at higher energies, described by a Grand Unified Theory (GUT). Beyond that, gravity remains to be unified with the other forces, in a Theory of Everything at the "Planck scale". While such investigations are well beyond the reach of experiments, they are important for our conceptual understanding of the fabric of the universe, as well as its origin and ultimate fate. Superstring theory provides a mathematically consistent framework for unifying all of the forces, including gravity, into a single quantum theory describing interacting, vibrating strings. String theory actually comes in a number of apparently different varieties, which are however related by symmetries suggesting a deeper underlying theory which has been called M-Theory.

For over a decade and half, Dr. Gerald Cleaver has been investigating possible (near)-minimal supersymmetric standard models and supersymmetric grand unified models constructed from superstring theories. Currently Dr. Cleaver is performing a more global investigation of the “String Landscape,” the collection of all possible string/M-theory models. Dr. Cleaver is examining overall properties and phenomenology of the Weak Coupled Free Fermionic Heterotic String parameter space of the Landscape.

Since string theory contains gravity, it provides a means of studying both particle physics and cosmology, and Dr. Cleaver is also active in the Early Universe Cosmology and Strings Group of CASPER. More information can be found at Dr. Cleaver's home page.