THE R-AXION FROM DYNAMICAL SUPERSYMMETRY BREAKING

All generic, calculable models of dynamical supersymmetry breaking hav e a spontaneously broken R-symmetry and therefore contain an R-axion. We show that the axion is massive in any model in which the cosmologic al constant is fine-tuned to zero through an explicit R-symmetry-break ing constant. In visible-sector models, the axion mass is in the 100 M eV range and thus evades astrophysical bounds. In nonrenormalizable hi dden-sector models, the mass is of order of the weak scale and can hav e dangerous cosmological consequences similar to those already present from other fields. In renormalizable hidden-sector models, the axion mass is generally quite large, of order 10(7) GeV. Typically, these ax ions are cosmologically safe. However, if the dominant decay mode is t o gravitinos, the potentially large gravitino abundance that arises fr om axion decay after inflation might affect the successful predictions of big-bang nucleosynthesis. We show that the upper bound on the rehe at temperature after standard inflation can be competitive with or str onger than bounds from thermal gravitino production, depending on the model and the gravitino mass.