We propose a four-dimensional N = 1 supergravity-based Starobinsky-type inflationary model in terms of a single massive vector multiplet, whose action includes the Dirac-Born-Infeld-type kinetic terms and a generalized (new) Fayet-Iliopoulos-type term, without gauging the R-symmetry. The bosonic action and the scalar potential are computed. The inflaton is the superpartner of the Goldstino in our model, and supersymmetry is spontaneously broken after inflation by the D-type mechanism, whose scale is related to the value of the cosmological constant.

Abstract:We consider Abelian tensor hierarchy in four-dimensional N = 1 supergravity in the conformal superspace formalism, where the so-called covariant approach is used to antisymmetric tensor fields. We introduce p-form gauge superfields as superforms in the conformal superspace. We solve the Bianchi identities under the constraints for the superforms. As a result, each of form fields is expressed by a single gauge invariant superfield. We also show the relation between the superspace formalism and the superconformal tensor calculus.

We propose a new class of inflation models in supergravity with higher derivative terms. In those models, the Kähler potential does not contain the inflaton multiplet, but a supersymmetric derivative term does. In the models, inflation is effectively driven by a single scalar field with a standard kinetic term and a scalar potential. Remarkably, the so-called η problem does not exist in our models.

Abstract:We complete the four-dimensional N = 1 superfield description of sixdimensional supergravity. The missing ingredients in the previous works are the superfields that contain the sechsbein e ν 4 , e ν 5 , e 4 µ , e 5 µ and the second gravitino. They are necessary to make the action invariant under the diffeomorphisms and the Lorentz transformations involving the extra dimensions. We find the corresponding superfield transformation laws, and show the invariance of the action under them. We also check that the resultant action reproduces the known superfield description of five-dimensional supergravity through the dimensional reduction.

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