The superconformal action can be gauge-fixed in a gauge where it leads to the Einstein frame supergravity defined by a Kähler potential \( \mathcal{K}\left(z,\overline{z}\right) \) , or in a gauge where it leads to a Jordan frame supergravity defined by the frame function \( \Omega \left(z,\overline{z}\right) \) , in addition to \( \mathcal{K}\left(z,\overline{z}\right) \) . We present new supergravity ξ-attractor models with non-minimal gravity coupling. They describe potentials with an exponential and a polynomial approach to the plateau. The previously known ξ-attractors in the large ξ limit predicted the spectral index ns = 1 − 2/N and the tensor-to-scalar ratio \( r\to \frac{12}{N^2} \) . The new ξ-attractors in the large ξ limit predict ns ≥ 1 − 2/N and r → 0, which provides a better match to the recent observational data and makes these models a target for the future B-mode experiments with small r.
New ξ-attractors have some features similar to those of Palatini attractors. However, we show that the Palatini gravity with nonminimal scalar coupling and an independent affine connection has no supergravity embedding.
