C. Pallis
We consider models of chaotic inflation driven by the real parts of a conjugate pair of Higgs superfields involved in the spontaneous breaking of a grand unification symmetry at a scale assuming its value within the minimal supersymmetric Standard Model (MSSM). We combine a superpotential, which is uniquely determined by applying a continuous R symmetry, with two fractional shift-symmetric Kähler potential s introducing two free parameters ( p , N ) . The inflationary observables provide an excellent match to the recent Atacama Cosmology Telescope data for 1.355 ≤ p ≤ 6.7 and 6 × 10 − 5 ≤ N ≤ 0.7 . The attainment of inflation allows for sub-Planckian inflaton values and possibly detectable primordial gravitational waves with ( p , N ) values of order unity. A solution to the μ problem of MSSM and baryogenesis via nonthermal leptogenesis can be also accommodated by embedding the model into a B − L extension of the MSSM.