String-derived flavor structures and their phenomenological aspects

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The purpose of this research is to clarify which flavor structures can be derived from superstring theory and to study their phenomenological implications.Recently, several discrete non-Abelian flavor symmetries were proposed to derive realistic mass matrices for quarks and leptons. However, their origins are not clear in 4D field theories. In 2006, we clarified that geometrical structure of compact space can provide their origins in superstring theories and typical flavor symmetries, which can appear from heterotic orbifold models, are D4 and Delta(54). In 2007, using these results, we studied which types of quark/lepton mass matrices can be realized from D4 flavor symmetries. Furthermore, when we consider supersymmetric theories, flavor symmetries constrain not only fermion mass matrices, but also mass matrices of their superpartners, i.e. supersymmetry breaking terms. We also studied specific patterns of supersymmetric breaking terms, which are predicted from the above D4 flavor symmetries.In addition, we computed higher order couplings, i.e. their moduli-dependence. We also studied moduli stabilization, and supersymmetry breaking and their phenomenological implications.