String theoretic QCD axion with stabilized saxion and the pattern of supersymmetry breaking

Abstract

String theoretic axion is a prime candidate for the QCD axion solving the strong CP problem. For a successful realization of the QCD axion in string theory, one needs to stabilize moduli including the scalar partner (saxion) of the QCD axion, while keeping the QCD axion unfixed until the low energy QCD instanton effects are turned on. We note that a simple generalization of KKLT moduli stabilization provides such set-up realizing the axion solution to the strong CP problem. Although some details of moduli stabilization are quite different from the original KKLT scenario, this set-up leads to the mirage mediation pattern of soft SUSY breaking terms as in the KKLT case, preserving flavor and CP as a consequence of approximate scaling and axionic shift symmetries. The set-up also gives an interesting pattern of moduli masses which might avoid the cosmological moduli, gravitino and axion problems.