Low energy aspects of superstring theories

The effective theory obtained as low energy limit of theE ₈×E ₈ superstring is analyzed from the phenomenological point of view. The supersymmetry breaking manifests itself in the low energy sector only after the radiative corrections involving the goldstino field have been taken into account. A universal mass for the scalar fields, generally smaller thanm _3/2, is generated. An intermediate scale can be obtained through the radiative breaking of part of the gauge group. As a consequence, the additional particles present in the spectrum get a heavy mass, and effective interactions are induced, which make possible the breaking of the electroweak group and the radiative generation of gaugino masses.