$$\alpha $$ α -attractor from superconformal E-models in brane inflation

Abstract

Abstract In the large extra dimensional braneworld inflation, Friedmann equation is modified to include a quadratic term in energy density with an additional parameter $$\lambda $$ λ called brane tension in addition to the usual linear term. The high energy brane corrections modify the slow-roll parameters and affect the behaviour of inflation. We analyse the superconformal inflation for E-models and find that there exist $$\alpha $$ α -attractors in brane inflation. The predictions for the scalar spectral index $$n_s$$ ns and the tensor-to-scalar ratio r are computed numerically, and approximate analytic formulas in the high energy limit have been given for the observable $$n_s$$ ns and r. The constraints on the model parameters are obtained by using Planck 2018 and BICEP2 observational data.