arXiv subjects
Publications and source records attributed to Sergio Ferrara.
A recollection of some theoretical developments that preceded and followed the first formulation of supergravity theory is presented. Special emphasis is placed on the impact of supergravity on the search for a unified theory of fundamental interactions.
We consider open strings in an external constant magnetic field $H$. For an (infinite) sequence of critical values of $H$ an increasing number of (highest spin component) states lying on the first Regge trajectory becomes tachyonic. In the limit of infinite $H$ all these states are tachyons (with a common tachyonic mass) both in the case of the bosonic string and for the Neveu-Schwarz sector of the fermionic string. This result generalizes to extended object the same instability which occurs in ordinary non-Abelian gauge theories. The Ramond states have always positive square masses as is the case for ordinary QED. The weak field limit of the mass spectrum is the same as for a field theory with gyromagnetic ratio $g_S=2$ for all charged spin states. This behavior suggests a phase transition of the string as it has been argued for the ordinary electroweak theory.
We perform a model-independent analysis of the spontaneously broken phase of an $SU(2)\times U(1)$ supersymmetric gauge theory, by using a non-linear parametrization of the Goldstone sector of the theory. The non-linear variables correspond to an $SL(2,C)$ superfield matrix in terms of which a non-linear Lagrangian can be constructed, and the pattern of supersymmetry breaking investigated. The supersymmetric order parameter is the V.E.V. of the neutral pseudo-Goldstone boson. Some applications of this technique are considered, in relation to the minimal supersymmetric standard model, and to determine the $g-2$ of the $W$-bosons in the limit of large top mass.
We show that in special Kähler geometry of $N=2$ space-time supergravity the gauge variant part of the connection is holomorphic and flat (in a Riemannian sense). A set of differential identities (Picard-Fuchs identities) are satisfied on a holomorphic bundle. The relationship with the differential equations obeyed by the periods of the holomorphic three form of Calabi-Yau manifolds is outlined.