The work proposed here is aimed at a deeper understanding of the basic laws and forces of nature. It is based on string theory and Supersymmetric Gauge Theories. These are theoretical models which combine quantum mechanics and gravity with the other forces of nature in a unified framework. Although lots of progress has been made in connecting String Theories and Supersymmetric Gauge theories to the Standard Model of Strong, Electromagnetic and Weak Interactions, as well as to big bang cosmology, new insights will be needed to make this connection stronger so that String Theory and Supersymmetry can be tested in the laboratory and observatory. This proposal is to foster serious international collaborations between the very strong string theory group at the University of Chicago, with some of the premier groups in Europe, Israel, and India. The subjects that will be investigated are at the very forefront of ideas on how to better understand Supersymmetric Gauge Theories and relate them to the Standard Model. Also of great importance is understanding Black Hole Entropy and how big-bang cosmology can emerge from string theory and brane-world physics. The PI's and collaborators have been leaders in the past few years in making progress in these areas, and by improving the mechanism for international collaboration that this grant will provide, one can expect an increase in the progress in these very important areas. The international collaboration will lead to new ways of looking at the problems confronting String Theory by having diverse talents and perspectives taking a fresh look at the issues. American Students and Post-Docs will benefit in being in diverse research and cultural environments and will benefit from being exposed to these interactions and environments. The collaboration will involve not only culturally different points of view, but also involve public lectures of the International collaborators at their partner institutions
